What it actually says on p37 is
If superior (S) in close combat in enemy bound:
+ 1 if scoring more; and mounted against foot
+ 1 if scoring less; and foot against mounted or foot
- 1 if Inferior (I) troops scoring less
The blank line separating the (S) adjustments from the (I) indicates this is a separate item. If you look carefully you will see that each case is separated by a blank line, i.e.
(S) in distant
(S) in close, own bound
(S) in close, enemy bound
(I)
(F)
This is one of several things in the rules that are obvious when you know what is intended, but are otherwise easy to misunderstand, or just hard to understand at all.
Lawrence Greaves