I agree with Dan as it sounds like you are actually using the credit line.
Look to Reg. E's OSC at 205.12, — Determining applicable regulation. i. For transactions involving access devices that also function as credit cards, whether Regulation E or Regulation Z (12 CFR part 226) applies depends on the nature of the transaction. For example, if the transaction solely involves an extension of credit, and does not include a debit to a checking account (or other consumer asset account), the liability limitations and error resolution requirements of Regulation Z apply. If the transaction debits a checking account only (with no credit extended), the provisions of Regulation E apply. If the transaction debits a checking account but also draws on an overdraft line of credit attached to the account, Regulation E's liability limitations apply, in addition to §§226.13(d) and (g) of Regulation Z (which apply because of the extension of credit associated with the overdraft feature on the checking account). If a consumer's access device is also a credit card and the device is used to make unauthorized withdrawals from a checking account, but also is used to obtain unauthorized cash advances directly from a line of credit that is separate from the checking account, both Regulation E and Regulation Z apply.
So you may need to look at "Z" and see what disclosures may be needed.
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AndyZ CRCM
My opinions are not necessarily my employers.
R+R-R=R+R
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell