Customer Service is not just support answering speed. It's how often you need to contact support, do they really solve your problem or needed to escalate it. In 90% of cases, we didn't have any issues and was bombing the support with common questions to see how fast they are. Indeed, BitDice responded very fast. But with BitDice one of use had uncredited deposit after many confirmations and this took BitDice sometime to resolve it.
We are open to every feedback, especially from a well-respected member like you. Rating will change over time, based on community feedback.
Then explain this in your review. Did something odd happen on every other site that you gave < 98 rating to for customer support, but praised their fast responses or stated that "The support system is great" (Bitvest review, gave 88). How about "The customer support for Primedice is excellent because its available 24/7 and they also have a live support chat with really friendly staff." (Primedice review, gave 97).
I'm still not buying that in your own words, a slow support is worth 98% while a great support system is only worth 88%. I'm not buying that a excellent customer support available 24/7 with friendly staff is 1% worse than a site with slow support.
Clearly there is a reason you're favouring BitGame as those ratings make zero sense otherwise. How much did BitGame pay you for the positive review?