++ Props for the 'actual testing' as opposed to speculation.
Of course, this is all dependent on temperature, if the ice is in sunlight or shadow (I've seen a 16cm ice screw melt out on a 20 degree day in less time than it took the leader to complete the pitch, when I seconded it I pulled the screw out without unscrewing it), lots of little factors.
Ice Climbing is risky business, and we're each putting it on the line every time we go out and swing our tools. Personally, weather I clip into the anchor or not as the leader has more to do with the next pitch and how sturdy the anchor is than any 'habit'. If it doesn't look like I'll get a solid placement for 15 feet (chandelier or aerated ice), probably better off not clipping the anchor (or placing a screw just off the anchor, as high up as I can reach from the belay stance). If everything looks kosher and the belayer perfers to, I'll clip through the anchor. Evaluate risks for yourself, and use what you believe is the best technique for YOUR situation.
Be safe out there. Oh, and clip a screamer on those crummy 'psychological' placements, they might be better than you think!