Gunny - I've not had any clear weather here for days now to carry out another auto-centre and record mount logs for 10 Micron. I will do so though when it clears. 10 Micron have asked for logs using their new firmware.
Ken - I'm sure you know that for accurate unguided exposures time is regularly synched between PC and the mount control box, using the Meinberg utility for example (I use this). The time synch option in Per's driver is to synch on slew, ie not when capturing a sub, but when the mount is instructed to slew as it would do in the auto-centre process. Time synching can also be used from a GPS. From time-to-time the mount control box firmware has to be updated with Earth Rotation data too.
I am sorry but I do not know how the time synching happens at a coding/scripting level: apologies if I'm not using the correct programming terminology.
Barry