The psychologist should be able to answer your questions about how to interpret the scores.
FWIW (and I'm not a professional) I've seen a lot of scores for gifted kids on this forum, and a lower PSI is not at all unusual. Sometimes, it's because GT kids are more meticulous and not speedy with the timed tasks for those subtests. It can also be related to fine motor issues. Unless you have noticed everyday behaviors that you think might be related to lower processing speed, I wouldn't be too concerned about it.
