Help! Business Booms and promoting your business, worse than useless?

So my character is building a temple for RP reasons, but I want to squeeze as much out of it mechanics-wise as possible. There are spells that buff your buildings, so I look those up, find Business booms, and... well, it seems like it actively harms your business. Here's what I've got: (Relevant rules here under "Promote a business" and here at "Business Booms".)

So when you normally promote a business, it spends your day of downtime. This "increases activity at the site". The effect of this is to choose one type of capitol that the building generates, then you can make a skilled work check to earn that capitol type using diplomacy, knowledge (local) or spellcraft.

This seems mostly useless given that instead of promoting your business, you could have just spent your day making a skilled work check. Unless your spellcraft or knowledge (local) is better than any other skill you could have rolled against, there's no advantage to promoting your business over just making a skilled work check.

When promoting a business, you can spend a point of capitol to add +5 to your roll. Because every 10 you roll allows you to generate one capitol at half-price, this rule allows you to trade 2 of one good for the opportunity to buy another at half price. This is almost always a trap choice, but does come out net positive if you spend two goods or labor (40 gp) to buy one magic capitol at half price (50 gp value).

The "increased activity at the site" lasts 1d6 days. What does this mean? Well, it doesn't seem to affect your roll. The description says you use the skilled labor roll "to determine how many additional resources the business generates over the course of this increased activity." This implies that the actual time doesn't matter. If you roll a 1, you get those additional resources "over the course of" one day. If you roll a 6, it takes 6 days to get these extra resources. At best, this is flavor. At worst, this is a cooldown mechanic. If your GM determines that "increased activity" doesn't stack, and you need to wait for one "increased activity" to end before another begins, then you can only promote your business every 3.5 days on average. (or 4.5 days if your GM rules that the increased activity doesn't begin until after you finish the promotion.)

So AFAIK that's the analysis of the "Promote a business" action. So how does Business Booms change this?

• You still must spend the downtime promoting, meaning this spell saves you no time.
• The spell "maintains the influx of activity" for a number of days equal to half your caster level. If you cared about promoting your business, this actively harms you at level 8 and higher, because it increases the cooldown between promotions.
• You needn't spend additional downtime to promote the building. You didn't need to anyway? After one downtime action, the building stays in its "increased activity state" whether you continued promoting or not.
• You must spend capital as normal to promote the building. Normally, you don't need to spend any capitol if you don't want to. But even then, this basically says "this spell doesn't change the way spent capitol works."
• The capital the affected building generates for you is unaffected by the spell. Again, this is a clause saying "This spell doesn't change anything."
• If you promote a different building, the spell immediately ends. I guess this means if you had two buildings generating capitol independently, then you could use this spell, then promote a different building the next day to shorten the cooldown on your "promote a business" action down to one day by ending the influx early, but that's a really roundabout advantage.
• It also costs 10 gold.

The whole Business Booms spell seems nonsensical... unless you assume that instead of making one roll "over the course of [the] increased activity," you make one roll per day. In that case, the spell increases your number of rolls from 3.5 on average to 4 at level 8 and 5 at level 10, eking slightly more per "promote a business" action. (Though it's a trap at level 7 when it lowers your duration from 3.5 average to 3 average.) Also, you'd have to spend capitol normally despite the increased duration. The spell description suddenly makes a lot more sense.

The problem is, that's not what "promote a business" says. It very clearly says "Over the increased duration". And for good reason: if you could spend one day promoting to get an average of 3.5 extra skilled work checks, then there's no reason not to promote your business whenever it's possible to, even if your diplomacy/spellcraft/knowledge(local) is crap. Making one roll per 1d6 days seems obviously RAI. It's almost as though Business Booms was written by a different designer that misread the "Promote a Business" rules.

Am I missing anything here?