I find that happens a lot. I keep my hatchlings in identical enclosures, and feed them at the same time on the same stuff...it's not uncommon for the majority of them to shed on the same night.
I've had similar things happen lots of times. When you keep a few things of the same age being fed at the same time they'll often slough at the same time. I think my two barkly adders (one of which is my avatar ) sloughed simulataneously three out of their first four times after I bought them, although not quite to the minute like your bredli