Litany of Weakness cast on fatigued characters

[Deadalready]

Litany of Weakness
Your litany proclaims your target weak, sapping its strength. The target is fatigued for 1 round. While subject to this spell, the target cannot be the target of another spell that has the word "litany" in the title.

Fatigued
A fatigued character can neither run nor charge and takes a –2 penalty to Strength and Dexterity. Doing anything that would normally cause fatigue causes the fatigued character to become exhausted. After 8 hours of complete rest, fatigued characters are no longer fatigued.

This might be as simple as open and shut but:
If I cast Litany of Weakness on an already fatigued character, does that qualify as him becoming exhausted?

Basically if the character does anything that would normally cause him to become fatigued (while fatigued), he goes one step further into exhaustion. So by using Weakness on him it causes an already fatigued character to become fatigued again changing his status to exhaustion?

[Archaeik]

Compare Touch of Fatigue

I would expect a pre-fatigued target of LoW to become exhausted since there's no restriction on the stacking.

Now, the curious question of what happens if the other fatigue effect is ToF -- I expect you'd get some table variation, but it probably shouldn't stack since it creates a weird exception where ToF is aiding the application of exhaustion while it says it cannot[should not].