I am assuming you meant millimeters......as in the fronts are at 10mm and the rears are at 7mm......I could be mistaken but pad thickness is generally measured in mm, tire depth is generally expressed as 32's of an inch.I have 10/32 on the front and 7/32 on the rear at inspection last month. I was thinking towing has wore out the rears faster.
Anyways, your pad wear, if it was mm is minimal....the fronts start at 11mm, the rears start at 8mm.....the rears have less work to do and are not as thick as the hard working, but larger, front pads.
Trailer pulling (trailer stopping) will affect front and rear pads.....not a particular axle.
How many miles on your car?