Line height where line is empty, vs with one or more chars

As I continue to compare my app using wp4 vs wp6, I find another difference. One line of a merged doc sometimes is empty, and sometimes has some chars. If empty, the line height is slightly less. I have the following code.

rtfMerged.FormatOptions       := rtfMerged.FormatOptions + [wpUseAbsoluteFontHeight];
rtfMerged.FormatOptionsEx    := [wpDontIgnoreSpacebeforeOnTopOfPage,wpDontAddExternalFontLeading];

I solved the problem by using a space instead of an empty string, but isn't there a nicer way?