10hr Timecode for TVC makes no sense in FCP timeline

I’ve been asked to prepare a series of 10 second clips for a TVC and have specific output requirements including the Clock Slate / Clock Number etc for clearance.

Im confused with the timecode requirements as this means adding an extra 10hrs so the clock starts from 09:59:50:00..

This has made the overall output file MASSIVE!!! 850g.b where as the original was 1.34gb.

Surely im doing something wrong, does the timeline have to be this long in FCP? Or is there something simple I can do to not have to supply the files with the extra 10hrs of pre roll?

Hope this makes sense? :)