Hi Charleski
One of the pleasures of MR is that we may have constructive threads. Thanks all of you for your insight and research on this field. To be honest, I really did not dig so deep in superscript.
To sum it up for my point:
Writer2xhtml produces an xhtml code which is very respectful of standards. One of its advantages is to drastically reduce the necessity of code tweaking.
The latter remains necessary at times, for example for drop-caps and nicely customized superscript tags.
Somebody disagrees?