Typically planting depth refers to top of the bulb up, but no worries. I've planted Daffodils much more shallow than recommended and they were fine. I've read that shallow planting allows for faster increase, but not sure if that's truly the case. In some areas with hard to dig soil, I plant on the shallow side, then add an extra deep layer of mulch to compensate, and that works just fine too. Those big Daffodil bulbs can be a real booger to plant at the recommended depth!
I've also planted Daffs this late in years past, and they bloomed the following spring just fine. They were a bit later to bloom than usual, but corrected themselves the following spring, so I believe you'll see a colorful show come spring
