You are required to include the total sales price for credit sales (1026.18(j)). Although I would generally not advise including this disclosure when it isn’t required, I don’t believe it would be a violation to include it because of the language in 1026.18-1 where it says disclosures under this section “need” only be made as applicable; it does not say “should”, “must”, or “may” which leaves some room for disclosing when not required. However, since this is not required for non-credit sale transactions your auditor/examiners may interpret the inclusion of this as a misunderstanding of the regulation, cite it as a violation and see it an indicator that there may be broader issues with your disclosures. I would recommend only including this as required – document the issue, make adjustments to correct the process, train, etc. and you should be fine.