[URGENT] Using 44AD for income from business revenue participations

Hi there,

So, I 20M, filling ITR for the first time. I do web developments freelancing and have client all across the globe. But there is this one client from Germany who contributes to 80% of my income.

I have a "contract" with company, and am the CTO and kind of a partner. And have 2 sources of income through them:
1. Hourly billing for my services
2. A revenue participation deal of 2.5%

Now, I am planning to declare my entire income under section 44ADA, and show 50% expenses. But as this client is more of a business partner to me (or vice versa), can I declare the income from this client under section 44AD, and save a lot more tax declaring 6% income? While keeping all other income under 44ADA ofcouse.

Questions:
1. Can I do this? If No, why?
2. If No, can I declare just the income coming from just 2.5% deal, under section 44AD, and atleast save tax on that? as that is purely from business relations, and will continue even if I stop providing services. One may argue as it is in percentage, it may be close to commission, which is not allowed in 44AD. But every partner in any firm earns a "percentage" of the profit apart from salaries.
3. Any other advices/tips/knowledge regarding this?