Building a migration business case when you're juggling 8 separate AI subscriptions—how do we actually model this?

We’re in the middle of evaluating a move from proprietary BPM to open-source, and honestly, the financial side is making my head spin. Right now we’re paying for separate subscriptions across different AI services, and on top of that we’re looking at Camunda licensing costs that are just… a lot.

The problem is that our finance team keeps asking for a clear ROI model, but every time I try to sketch one out, I end up with this massive spreadsheet where half the line items are question marks. Like, we know we could save money by consolidating to open-source, but does that savings get eaten up by the cost of migration itself? And how do we even account for the AI model costs during the transition?

I’ve been reading about platforms that give you 400+ AI models under one subscription, which theoretically means we could stop bleeding money on individual API keys. But I’m struggling to figure out if that actually changes the math for a BPM migration, or if it’s just moving costs around.

Has anyone actually built a solid cost model for this kind of switch? I’m specifically curious about how you account for the actual AI model usage during migration planning and execution when you’re consolidating from multiple subscriptions. Do the savings calculations actually play out in practice, or are there hidden costs that mess up the projections?

We dealt with exactly this mess last year. We had Camunda plus about six different AI tools bolted on, and the licensing was out of control.

Here’s what actually worked for us: we stopped trying to model everything at once. Instead, we picked ONE small process—something like invoice routing or document classification—and ran it through both scenarios. Old setup versus the consolidated approach.

Turned out the math was pretty different than what our spreadsheet said. The setup cost for migration was real, yeah, but the monthly savings on API calls and licensing were bigger than expected. We were overpaying for AI services we barely used.

For your model, focus on execution volume first. Count how many times your workflows actually call AI services per month, then map that to pricing. A lot of people guess way too high on usage, which skews everything.

Don’t try to model the entire migration cost upfront. That’s where most plans fall apart. Work backwards from one or two high-impact processes.

One thing we learned: consolidating to one subscription doesn’t magically fix things if you’re still running inefficient workflows. We saved money, but only after we actually looked at what we were automating and why.

The 400+ models thing is real, but it doesn’t matter if you’re not using them right. You need to pick the right tool for each task, not just grab whatever’s available. That’s where the real savings come in—using the right model at the right time, not overengineering everything with GPT-4.

For modelling purposes, separate out the platform cost from the execution cost. One subscription gives you access, but you still pay for what you run. That distinction matters a lot when finance is looking at burn rates.

The key insight I’d offer is that the migration itself is actually where you can test your business case. Instead of modeling everything theoretically, consider using templates or a no-code builder to prototype your migration on a small scale first. This gives you real data instead of guesses.

When we modeled our transition, we took one department’s processes and ran them through the new setup for a month. The actual results—error rates, execution counts, integration time—became our baseline for projecting the full migration ROI. It was way more accurate than any spreadsheet estimate.

The consolidation of AI subscriptions helped, but the bigger win came from being able to actually test the theory before committing to the full switch. That risk reduction alone was worth the pilot.

The challenge you’re describing is common because most organizations conflate platform migration costs with AI consolidation savings. These are separate financial dynamics that need separate analysis paths.

For the subscription consolidation piece, start with vendor spend audits. Track which AI services you’re actually using and at what volume. Many organizations have unused API quotas or overlapping tool coverage. That audit becomes your cost baseline.

For the BPM migration itself, cost modeling should account for data mapping efforts, workflow redesign, testing cycles, and training. The AI tools help with automation of some these tasks—particularly workflow generation from process descriptions and autonomous testing. That’s where the consolidation to one subscription actually impacts migration timeline and cost.

Start with actual usage data. Run a two-week audit of your current AI tool spend. That’s your real baseline for ROI calculation.

The core problem you’re facing is that you’re trying to model the entire migration financially without any way to actually test the assumptions. That’s backwards.

What we did was use a platform that consolidated the AI model access and also had templates and a no-code builder. It let us prototype the entire migration workflow—data mapping, integration testing, process validation—without needing a six-month dev cycle and without guessing at costs.

Instead of that spreadsheet with question marks, we actually built out the migration process itself. Ran part of it. Measured real execution costs, real integration time, real error rates. That became the financial model, not some theoretical calculation.

The 400+ AI models in one subscription sound abstract, but operationally it means we stopped paying for individual services and just paid for what we actually executed. The cost visibility is way better because everything runs through one system.

For your case, you need to move from estimation to measurement. Build the migration workflow, run a pilot, get actual data. That’s how you build a business case that finance will actually trust.