FL Studio 12 plugin delay compensation was problematic, with noticeable delays of up to 15 microseconds and severely out of time, whereas in FL Studio 20, problems with the PDC has been fixed.FL Studio 12 didn’t give you the option to program time signature changes, whereas FLS Studio 20 works with multiple time signatures.FL Studio 12 might require you to use Boot Camp on your Mac machine to install it for Windows, whereas FL STudio 20 has native macOS support available.
The Main Differences between FL Studio 12 vs FL Studio 2 are:
Main Differences between FL Studio 12 vs FL Studio 20