Perm Enlarge / Alter Self Interaction

[Jesalin]

Rules wrote:

You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.

Does this mean that a character could get a Permanent Enlarge cast on them, and then use Alter Self (which is a polymorph effect, unlike Enlarge) to temporarily shut down the Enlarge, and be size Medium or Small when convenient?

[happykj]

Yes, as the rule said, any spell that change your size has no effect under polymorph spell, unless otherwise stated