Back in the day--my old dad was an Authorised Person-- to officiate at ( JW ) weddings. ( In the UK ).
Over the years he attended numerous weddings in the West Midlands--and he was a stickler for the official vow words had to be used.
He told me that At one wedding--the person conducting the ceremony decided to use his own words--and my dad stopped him and insisted he use the exact words in the script. I dont think he was too popular after that.
He told me the reason he was strict about it was in case of any future marriage bust up--the use of unauthorised vow words could result in the marriage being declared nul and void.