The 7.8% increase is based off of in person USPS location retail prices, so if you are using Ebay/Pirate ship then that would be like 15 - 30% less than a 7.8% increase if I'm reading it right but it gets confusing because of the current holiday upcharges what it would specifically be after.
If you are selling on Ebay this crossposting app I pay to use recommends only using set shipping rates instead of calculated because google's search engine can't calculate the item price per region/buyer so set shipping rates appear higher in google searches. They get the info straight from Ebay employees and w set shipping charges you will pocket a few extra bucks to cover packing/supplies as well. You set up ALL shipping via business policies which ironically most of the Ebay "gurus" on Youtube had been preaching not to use for quite some time lol.
I have set shipping business policies $6 1 - 8oz $8 9 - 15oz $10 1 lb - 1 lb 15oz $12 2lb - 2lb 15oz West Coast items I make less than a dollar typically or break even I'd guess HI/AK i'd lose a buck or two. PR I lost $2 - 3 bucks a few weeks back on an item, if you get offers the state typically shows up once you open the offer up! Once you set up all the weights/prices you need for shipping business policies there's a toggle menu for each new item you list that helps to streamline listing