It was indicated that the High Balance is used in place of the credit limit for utility calculations, when no credit limit is reported.
I wish it were, but in my experience, this is not the case with EQ, EX, or TU. Please note that I am not referring to a balance, but a high balance.
YMMV, but whether there is a zero balance or a balance reported, the high balance is not used in place of the credit limit.
Depending on the balance reported as Fused mentions, it doesn't seem a lot of points are lost, especially if the account is reported as Open.
What is lost is the amount of available credit you would have had had the credit limit been reported.
BOA reports their Visa Signature as Revolving/Flex Type account to all three CRAs and refuses to report it as Open/Flex Type.
