Dual CS5000 arm lifts before end of recording

Frequently my Dual CS5000 arms lifts before the end of playing a 78RPM recording. Reversing the turntable by hand sometime corrects the problem. Other times I can play many 78 recordings without experiencing the problem. Never have the problem with playing 33-1/3 recordings. Anyone know what the problem is?
The cueing lifts at a preset point. That distance is adjustable.
The problem is if you move the lift point to accomodate the smaller 78 disks, then you will never have the arm lift at the end of the slightly larger center label LP.
You could experiment ad move the lift point to the smallest taht allows lift on the normal LPs. then most of your 78's will go to the end.
(I own a Dual 7000, same thing as a Dual 5000 with a few flashy parts)