Double safety blitz audibling to something else.

I started using this on defense after watching a video and wondered if anyone else has tried this. Calling a play on defense where both or even just one of your safeties are blitzing and so they come down to about where the linebackers are and then audibling to something else like a cover 2 or cover 3...etc and the  safeties still stay at around the linebackers level. Seems like it can help vs the run and can throw your opponent off sometimes. I guess the only downside is that your safeties will have to back peddle more to get into their zone coverages but as long as you have good speed and make sure you dont get beat deep it seems like it works well most of the time. I use the 4-6 pb and it has  a dbl safety go  play out of the dime and one out of the dollar formations and has a few plays where one safety comes down out of the 3-3 formation where you can audible to something different while the safety still stays at the same depth as the linebackers,it helps with the run especially in the 3-3 formation that only has 3 D-lineman with usually a linebacker blitzing but I usually user the LB that is blitzing.