We have had a few situations where a customer has a HELOC and we may increase the amount of the line by a few thousand dollars. The loan officer does not wish to change the lien amount against their residence for this...so essentially we may have a HELOC with a line of up to $27,000, but only a security agreement for $25,000. Would we need to give a ROR for that additional $2,000. I'm thinking we should, but the loan officer is questioning why because we aren't increasing the lien against their residence?

An increase of the credit limit is a circumstance leading to the right to rescind for open-end credit. See 226.15(a)(1).