Most likely 88 hours was a "MAKE", which means you scheduled to forecast but either had calls off to account for 88 hours or sales going over forecast that gave you 88 hours. Even if you had Sales gains over forecast, most MGMT doesn't want hours added because they feel you might have less sales to forecast later in the week.
Our store frequently doesn't use all their hours. They refuse to properly staff the departments, so they are left with unused hours each week. And we are talking about a few hundred hours. Plus i don't work in one of those small stores, we a a million dollar a week (w/o fuel and Rx) stores.