I HAD this problem of the extruder skipping like crazy,new hotend,new tubes, took the extruder apart cleaned the ■■■■ out if, dried the filament, etc etc… put it all back together thinking that should fix it,but nope.,wierd thing I put in the old hotend that was basically wore out and it worked not bad,very few skips,but prints were horrible. I took the cover off the hotend and the silcone boot and noticed the hot end was jumping up and down when it skipped. What I found to fix it was the hotend mount 4 little bolts were a half a turn loose, all 4 of them.
I had read thru this on the wiki -A1 series printer extrusion abnormal troubleshooting
I am not familiar with the X1 or P series, but this is what fixed my A1