A priest I requested kindly to bless salt and oil did not use the prescribed prayer but used his own, is the blessing valid?

A priest I requested kindly to bless salt and oil did not use the prescribed prayer but used his own. Is the blessing valid? The prayer for exorcising the salt and blessing the oil was available. However, the vision of the elderly priest was poor and he could not read the prayer to bless/exorcise the salt and bless the oil. The priest then said that his own prayer is still valid and efficacious to bless the salt and oil. **Is his blessing on the salt and oil as valid or efficacious as the prescribed prayers for these items?**