I’m so pleased that I have been of some help. I will try to be so again.
I believe you have exercised a subtle misreading of the Spell description, and I will try to make it “obvious” to you. Of course, my own reading might be erroneous, so please take this provisionally.
To use Favor of the Gods, the sorcerer must cast Favor of the Gods and the Spell that is intended to be “stored.”
For example, let’s say that the sorcerer wants to store (found, for convenience here, on the same page) Form of a Beast. Right here the GM must make a ruling, as we discussed, on the Spell Favor of the Gods, i.e., must the sorcerer already know this Spell or might s/he choose any Spell? As you know, I prefer the latter interpretation.
Now, to actually “store” Form of a Beast, the caster must spend a Fortune Point and cast Favor of the Gods together with Form of a Beast. To make it interesting, let’s say the Form of a Beast effect the PC is going for is Cloak of the Wild, which is D1 and requires 2 Momentum. So, Favor of the Gods (D1) and Form of a Beast (D1) becomes a D2 test, with the PC requiring 2 Momentum (however one gets it, at this time, to gain the intended result).
Moreover, while casting Favor of the Gods, coupled with Form of a Beast, the sorcerer must spend 2 Resolve per the two Spell descriptions.
Finally, in play, the GM rules that the gods “trigger” Form of a Beast as a Free action on the PC’s part. The PC still must pay 1 Resolve per Round or Scene, per the description of Form of a Beast. Moreover, per the description of Favor of the Gods, the PC also effectively loses one “temporary” Fortune Point for as long as the Spell is in effect.
I think your subtle misunderstanding is in your reading( in the description of Favor of the Gods) of “another spell (or spells) that will be the actual spell whose effects will be felt.” In case the misunderstanding is deeper, Free Action in this context refers to the Action Table (Free, Minor, Standard); the caster is not “Free” to choose any spell at any time—the Spell still must be cast, as described here, at the time in which Favor of the Gods is cast, usually well before the intended favor is to be effected.