I have a vocabulary question as English is not my first language.
At the moment, my Standard shipping is set to Economy to keep the costs as low as possible but I offer at check-out an upgrade option, which is called Priority upgrade. Very few customers choose it. Since Economy shipping to the US can take up to 4 weeks, I specify again in my automated thank you message and in the message that I send to the buyers to let them know when their order will ship that the Priority upgrade is available.
Very few people actually read these 2 messages and when the US postal service is slow (which seems to happen a lot these days), they worry that their print hasn't reached them yet. They are usually understanding when I point out that the shipping timings were fully detailed in those messages but I would like to raise the visibility of the upgrade option.
If I change the wording from Priority upgrade to Expedited, will it be more explicit ? I would welcome the opinion of native English speakers.