Hangtime is in milliseconds, so 400 would only be 0.4s.
Hangtime is just the time that the transmitter will wait to unkey after the TX key signal has been released, and has nothing to do with squelch tail.
STE on Chinese radios is a weird Chinese implementation with something like a 55hz tone. It is completely different from any standard squelch tail elimination method used in the USA and should be left disabled.
I have found that all of the cheapo Chinese radios such as Quansheng have an audible squelch crash on their receive, regardless whether using CTCSS w/ reverse burst or cicken burst, or even when using DCS w/ turn-off code. Kinda just one of those things where you get what you pay for.