Honestly, I don't think that this fight will be that slow paced. Considering it will probably be a mid-close ranged fight. And besides Mogan semblance doesn't have to reach 10 seconds to work. The consequences of an impact start ramping up immediately, so for example, after 2.5 seconds they will be 1.5 stronger than the originals. Anyway, if we discover that the five seconds rule isn't practical or can't be applied for timing reason we can just change it.