Yes, every single recompilation may require the delay (depending on compiler and architecture) to be revalidated. C51 processors are extra affected because of the static call-tree analysis often performed. That is why C-only loops are possible, but should be seen as a last desperate resort when no other choices are available. They are so darn error-prone and in the long run very, very costly. Besides the cost of the constant validations, you also have to factor in the potential for a recall.

That the OP still requests source code for both a C-only and a timer-based delay can be seen as an indication that the posts have not been fully read/understood, or that this may be a school assignment requiring multiple solutions to be submitted.