To add to the above, when checking the wiring connections, check both for good connections, but also look for dirt and wetness. I used to have an actuator that was pretty dirty, and whenever it rained, the connections would get wet, and they'd apparently short out to some extent, and I'd lose or gain counts, but when it dried out, everything was OK. (Ie clean water doesn't conduct much, but dirty water does.)
Another parameter is free play in the gears. Often you'll think you're losing counts, but actually what you're seeing is coming into the sat from 2 different directions, such that the free play in the gears makes the sat appear to be in 2 different places depending on whether the actuator is extending or retracting. Next time it doesn't hit the sat, go one sat further, and come back. If it hits it, it's probably loose gears.
Re the Skyvision "kits" , I've never had a Saginaw, and don't currently use an actuator at all, however a year or 2 ago, I bought a Skyvision "kit" to replace the reed switch on my H-H Atlas. When I got the thing, I was dissappointed because it was a cheap home-made thing that I could have made for a fraction of what I paid. It may be different though for actuators that have been made more recently, ie maybe they have access to real parts rather than having to make them.
However from what I've seen, those reed switches seem to fail by sticking closed, at which point you'd lose a LOT of counts. I'd really guess that if the thing seemed to be working most of the time, that the problem was poor wiring connections, and/or adjusting the spacing as mentioned above, if it is possible with that actuator. I've had some actuators that you could adjust, and other actuators that couldn't be adjusted.
It's also not out of the question that the receiver itself is putting out a dirty signal, as the caps dry out.