Can you withhold an ITF for future use for a later claim??

Let's say you have an ITF on file that expires in May and you want to use it to file new claims for condition X and condition Y prior to May.

Let's also say that you're already SC for condition W but you feel you got a bad C&P exam and got low-balled on your rating percentage and want to file to submit a private DBQ for a higher percentage for condition W.

Can you bank the ITF and not use it for the condition W and keep it for use for condition X and Y or will the VA automatically assign it to condition W? Is there any way to keep them from using it for W?

Would you file for a Supplemental or for an Increase for W (or something else entirely)?

TIA