it may not at 6k-but you can do the math. if you're using stock valve springs (I am assuming here), you're floating most definately as there is very little holding that valve closed at full boost.
Yeah, at 20+psi you are most likely floating the valves. You only have roughly 26-28lbs of seat pressure on them at that boost level. Running an aftermarket spring (most are in the 95-100lbs of seat pressure), you would have considerably more pressure keeping the valves shut at high boost.