You won't have any problems. I've done this in the past. If you can't make a new reservation for the 4 nights in a row, don't risk to cancel and rebook. You're set as you are.

By the way, there is a recent thread in which somebody explained that you can use a hotel certificate for non-consecutive nights like when you pay or use a Stay Anytime reward for a night in-between. That was pretty interesting.