I don't know why people are charging you that much for a problem from which you already have found the solution.
You haven't provided the source code, just the compiled one and unless you give the complete source code, I will need to decompile the code to make the changes but it's not a guarantee that the recompilation will then properly work without further changes.
My proposal would be:
1. either you submit the source code and I make the complete changes, test the and give them back to you, that should take 1 day at most.
2. or I decompile the code, make the changes, create another project with the said code to clean the noise the decompiler will produce, test it and if everything is perfect and then give you the new code and all the tested files but this will then take more than 1 day and will cost a bit more.