By combining they mean 'at the same time'. Because SFQ is one type of medative practice and Holosync another some people think combine them and save time.
This isn't good since holosync is design for specific brain entrainment and qi gong needs you to be a little more flexible. Somes you go deeper into the emptiness than others because you have different healing you may want to focus on.
Anyway if you do Holosync it is wise to leave at least 30 minutes between the two. Same as with following qi gong with other physical exercises... leave a break.
Alex