If the mkt goes to 1600 then VXX drops to 16 and when it drops 5% you get back to 21.
The market will not go over 1600 before it hits 1500.
If this is the mkt top, and it drops 5%, VXX goes to 26-27
If the mkt goes up to 1575 before dropping 5%, then VXX drops to 19 and then goes to 24-25.
So this price is a good area to buy VXX. Even if it drops to 19 you will still see 24-25 later.