Are the phones less than a year old? Applecare+?
I ask because having AC+ reduces the price considerably. And I also ask because if you don't have AC+ and you get the glass replaced while the phone is less than a year old you will effectively void the remainder of your one year warranty.
So, if later on (but still before a year is up) you need warranty service from Apple and they find a non-Apple OEM screen replacement you're done. They won't fix it.