Dustin Campbell's page

It's well-understood from the text that winds of certain strengths can disperse the various mist/fog spells. For example, fog cloud states the following:

A moderate wind (11+ mph) disperses the fog in 4 rounds; a strong wind (21+ mph) disperses the fog in 1 round.

My question is, does "the fog" refer to the "fog within the area of the wind" or "the entire fog produced by the fog cloud spell"?

This came up recently in a game where a single gust of wind was being used to disperse two adjacent acid fogs. Now, gust of wind says that affects a 60-ft. line, but acid fog has a 20-ft. radius. As the GM, I ruled that the gust of wind only affected a 60-ft. line within the acid fog based on the following reasoning:

1. Acid fog is a 6th-level spell. It seems wildly imbalanced (to me at least) for a 2nd-level spell to completely thwart it.
2. There are other wind-producing spells that affect a much larger area and would cover the whole fog (e.g. Control Winds).
3. An eversmoking bottle can produce up to a 100-ft. radius of smoke, yet has essentially the same text as fog cloud for how it interacts with winds. If gust of wind affects the entire fog produced by fog could, does that mean it would also affect the enter 200-ft. diameter smoke cloud produced by an eversmoking bottle? What if gust of wind only affected a single 5-ft. square of the smoke?
4. Obscuring Mist contains language which describe how the areas of effect overlap between it and fiery spells, such as fireball, flame strike, and wall of fire. I'm inclined to believe that wind spells are expected to overlap similarly, but it uses language closer to that of fog cloud quoted above.

I searched around but did not find any definitive answers. How are others ruling this?