I highly doubt that they'll retest her on the CogAT. It's poor testing practice to retest students (or adults) with the same instrument after such a short amount of time has passed.
It probably depends on the school and you're right that it is poor testing practice to do so. However, I do know of at least one GT coordinator local to me who has given kids the CogAT, OLSAT, and then the CogAT again within a matter of months when they missed the 95th percentile on one area cut-off for our GT programming. I'd agree that the scores are highly suspect at that point, but it does happen depending on the school.
What I'd remind myself is that the goal is ultimately to ascertain the child's needs and the right placement for the child not to get a high enough score to reach some artificial cut-point for a program. It gets hard, though, when others are prepping, retesting, etc. and it becomes such that other kids of similar ability are placed in programming for which they, ultimately, don't qualify either. That tends to leave the regular classrooms with kids with less pushy parents and lower achieving kids, which may not be a good fit depending on your child.
