I think it is pretty poor show if you purchase the 4 track recorder in the free app, then have to pay for it again in the pay for app it is pretty cheeky.
I'm sorry, but I don't think you understand exactly what's happening here.
The company you should be angry at is apple, not IK. IK are providing a program that works the way apple says it has to work. The in-app purchases work on the apple system. I'm sure that IK would like to give the option of associating the in-app purchases with the full version, however that's not something that's allowed for in the apple system.
www.manninmusic.com Music Teacher, Isle of Man