all it is, is wilson rebranding their frames. They want to separate these from the six one line thats why these are known as the pro staff 90, 95 and 100L now. just like you will see slight differences in the blade 104. older painjobs have it as BLX blade 101 newer ones have it as BLX Blade 104L same with the Juice 100 is now Juice 100L. as for the prostaff line i believe dropping hte six one is long overdue consider these frames were built off the 6.0 platform and not the 6.1
I still don't know why the older generations of Tour 90 were called "6.1/Six.One" when they were all clearly descendants of the Pro Staff 6.0 line.