[GMcG]

My understanding is, that spacing means a space, following a letter.
So the last letter of the g e s p e r r t word will get a space too, creating the spacing to the following comma.
You should exclude the last letter of the word. It is spaced to the preceeding letter, because that letter has a following spacing, but there is no spacing between last letter and comma.

Instead of
<span style="letter-spacing:3pt">example</span>, xxxxxx
use
<span style="letter-spacing:3pt">exampl</span>e, xxxxxx

George