The P Moon is a timing device much more then anything else. Aspects that it forms in its progression through the signs and houses relate more to the signs and houses that it is in and to the signs, houses and planets it aspects. The matters signified by all this will come to the fore when P Moon aspects natal, transiting or other progressed planets. It is more personal when Cancer sits on the Ascendant and to a lesser degree when Sun is in Cancer in the natal chart.
The Sun to is a timing device & is more personal when Leo sits on the Ascendant or to a lesser degree when Sun is in Leo in the natal chart.
The reason for that is the planet that rules the Ascendant is often called the "ruling planet" and its position, transits and progressions are very improtant.