It SOUNDS like there was an unrelated derogatory item to MS (e.g. an unpaid medical bill). This would explain the auto insurance rate issue.

When OP says "...have had higher revolving credit card charges (all of which are paid 100% in full prior to due date)" I get the impression that MS activities might not be paid off until after statement reports high MS balances, which certainly would hurt scores.

In order to negate the score impact from MS, it's important to pay off MS in full BEFORE the statement even cuts.