You will have to catch this situation in your app, say it remembers the no. of checks it has printed on the last used page, the next time assume the user will put the same page in the printer again, so you have to skip the first 1 checks and start printing on the next (second), after printing, remeber the new no. (2) and next time have the user select the actual no. of checks to skip. It should be 2, as you printed 2 checks so far, byt the user may want to get a new page, and needs to start with 0 skipped checks...
In your app, you already know the number of mm or inch to skip, multiply by the no. of checks, and the offset is born.
I hope this is a little clear, if not I'll rephrase ;-)
HTH
TonHu