When I made the jump from Tasks to Tasks Pro™ I added about 9000 lines of code. Version 1.5 of Tasks Pro™ represents the largest increase since that time, with the code growing to over 22,000 lines. That includes quite a few changes I made to make certain pieces of code more modular and reusable (reducing the amount of code from the previous version).
With that much new code, it’s no wonder I have so much more documentation still to write.