Pony Softball Pitcher Sub Rule Clarification

[jrp]

I have a question about pitcher substitutions in the 2005 Pony Softball rulebook.

Rule 4-3-b (second note) reads to me that you can swap pitchers as often as you like, with the only exception being you can return to the mound only once per inning.
Does this allow for using 2 pitchers, and alternating innings ?

I.E.
Inning pitcher 1, inning 2 pitcher 2, inning 3 pitcher 1, inning 4 pitcher 2, ... ?

In the 2004 Rulebook Rule 4-3, it states that a starting pitcher may return top the mound one time and a sub pitcher cannot return. Is this a rule change, or an attempt to clarify the original rule ? Could you please help me understand this rule.

Thanks.