Hi
Hope I don;t mis-understand your idea.
Just sharing my business model on using PowerApps as a Productivity Apps to complement some clients' existing SAP, ERP or even Excel-based system (
).
As an ISO/Qualty & EHS/Improvement Advisor, I would say that our experiences in clients' system will be added advantage for us to quickly developed apps as an additonal solution to expedite their daily routine, boring and yet unproductive tasks.
Hence, the amount of works which can be expedited with apps will determine the charges on clients. Since PowerApps is free, Excel is Free (I assume your clients are using Excel), workmail belong's to cient, nothing from the softward can be counted on them.
Again, total no of SCREENS / FORMULATION / TABULATION will be also a key for cost-calculation, definitely including amont of time (hours) spent on creating apps.
I have started with 4 clients (completed and under trial) and 2 more ongoing clients on using PowerApps. I would see the trend of using MOBILE Apps & Cloud Data (Excel) to assist Top Management to manage remotely from Mobile Phone, NOT PC.
Just sharing.