7-8 pttbb/100 certainly can be the goal, but 3-4 is very respectable, especially when multi-tabling. Maybe single-tabling where reads can be more accurately made and playing style tracked better 7-8 is a good goal, but for 4+ multi-tabling, these numbers are very good. I personally play 6-8 tables and am at about 2.5ptbb/100.

However, any positive win-rate is better than a losing player!