Altitude change for the 406 caravan.

[t4murphy]

When I first engage the altitude hold on the initial climb it works great by holding the altitude.  But when clicking ALT button off to climb or descend the ALT button reengages.  I usually have to click on and off several times to keep it off so I can pitch up or down to change altitude . I use the TDS750 and wasn't sure if that was a factor.