It's not that we don't inflate to the recommended pressure, it's a question of when the Crossfire says it is no longer spot on how far off it can be before we correct it. My contention is that thumping with a hammer doesn't know the difference between 100 and 90ish so just because the Crossfire tells me it is 3 or 4 pounds low what difference does it make? The reference chart tells me it doesn't as long as the load carrying capacity is still within limits.