Help with Grooming chunkers

I have been given some chunkers by a groomer, she had dropped them and there was a substantial ding in the blade.
I sharpened the way i normally would, making sure the ding had been removed.. all went as expected, sharpened really well, really good burr, the rideline went well, I polished, i know there are different ideas of what to do with the toothed side so i usually polish them and sharpen and polish the rideline. all went perfect. cut some tissue and they went through a dream. i gave them to the missus who is a groomer also, and they worked a dream. gave them back and the customer said they worked great on fine haired dogs, they worked great on thick haired dogs, but the dogs with in-between kinda hair they dont work, the last inch folds the hair (from where the ding was to the tip).

I took them back and got the missus to try and sure as, same thing. thinner coats, and thicker coats work great, but not inbetweens..

Any suggestions on what to try next with them? Hard to fix when they seem to be working for the most part..