Depends, why are you box squatting?
If it's as an assistance movement to build your posterior chain more than I'd sit back to an extent like all the Westside bros do it. If it's not though, I wouldn't.
Personally I think it's an okay exercise but not that great.
If you're looking to use it more as an alternate to squats (for variety or maybe an injury prevents you from doing it etc.) then what you're doing is more acceptable as you want to keep the form similar.
@Gallium: Wouldn't take a week off but a deload at like 60% is pretty beneficial. I'd do it when you feel like it. Not sure how you train so it's hard to say. Every 6-7 weeks is decent if you train very heavy/maximal weights. If not, maybe you don't. Maybe just deload for half a week. I'd try push it as much as you can though.