I didn't want to cut mine, but they were getting dry and a bit tough, and I could see where one was trying to pip but not getting through, so I cut (on the advice and with the assistance of a much more experienced local keeper). I think it was taking the press 'n seal off combined with a continually running circulating fan that did it. Mine seem to be coming out at a one per day rate now (although the first one was out within 5 hours of cutting). I've been taking them out of the egg tub so they don't disturb the other eggs, rinsing them with the bottles of water from the incubator, then putting them back in the 'bator in a separate tub. They seem content in there.

I'm not advocating cutting, but you may want to gently check that all of the shells are still pliable so they're able to cut through when they're ready.