I don't know a whole lot about powerlifting, but I feel like I've gotten lucky and am actually able to get seom decent carryover from a bench shirt so I'm going to try and help you out.
First of all, in my opinion your set up sucked. When you get in a bench shirt you really need to keep your upper back tight to keep you from collapsing and to pull the bar down to your chest.
Secondly, you're benching what like 300 pounds? and your what like a 198r or 220r. I'm not trying to make fun of the weight your lifting but you can't touch with light weight and apparently it's just too damn light. grab three spotters, sack up, and keep putting weight on the bar until you can get it too touch. side note: If you want to touch with a lighter weight, don't have some one yank down on your shirt. Let it ride up a little.
From the video it looks like you're just letting the weight drop and you clearly lose it out the front and it falls on the board. as whats already been said lower the weight under control until the shirt stops the weight, at this point you can either press it back up, roll up to touch, or try to row the bar down to touch.
what's your raw bench and previous shirt experience? any videos of you benching not in this shirt.
ps. that shirt isn't tight.