Question of the night/morning.

I got the bug to mix up some PMP tonight so, I just eyeballed it in a tumbler at 60:40 OTA/Weller 12. Tasted pretty decent. More like ORVW than the 15 though.

Is it true ,when trying a home blend, that you should let them sit for a while (like a week) before drinking them for optimal success? Thanks in advance for your input.

EDIT: if true, why? What happens in that week that can't happen in 15 minutes?