Auditors or examiners?
Auditors like to come up with all kinds of 'recommendations'.
As has been stated above, there is no regulatory requirement for documentation by a certain form.
It is prudent to have some kind of procedure, be it a form or a line on your processing sheet, that notes when and how the intent to proceed was expressed by the borrowers.
Whether you charge fees up front or at closing is immaterial.
I can vouch that EXAMINERS will ask when you got the OTP or ordered the appraisal, neither one of which, by Regulation, can occur till after you have delivered the GFE&TIL and received the intent to proceed.