It would help if we knew the stats on your other credit cards reporting to give you a general idea on where you'll stand.
The card will help you with both your AAoA by about another 2 yrs give or take and also (which I think is the bigger deal) getting the oldest card reporting from 3 yrs as you currently have to 10+ yrs with the AU add. Having your oldest card in double digit years will help a lot as you try to increase your score. Also depending on the limit on the AU card might help your total credit on hand as well actually. Your lates might limit that growth depending on how bad (30/60/90) the late is as well as how old they are but should still see an increase. This all assumes the AU card being added is in good standing.
There are some cases where some banks don't take AU cards into consideration but those are rare IME. For sure, though, if you're going to apply for a loan to cover this future business expense an UW will probably do a manual review of your credit and remove the AU from consideration since they don't see you having responsibility for that debt. If it's a credit card you're looking to cover this expense I don't see the harm in adding that 10 yr old card to your reports to improve your chances. What are your scores currently looking like?
Scores are all pretty much hovering around 700, even the older models. Trans union hates me for some reason, some of those scores are low 600's. I had one collection account with nationwide for $150 that I just paid for deletion. Hopefully that gives me a boost and trying the AZEO method. The collection was more of a principle thing not an inability to pay. Learned my lesson on that one lol
Assuming you mean FICO 08 scoring models you should be fine especially once you add that card to the mix if applying for a credit card. And yeah anytime you can get a PFD for a collection you take it especially if it's bring your scores down.
I just looked and apparently the only bereau showing an active collection is trans union. Guess I won't get an Eq or Ex bump. Also looked at the different score break downs and when you hit the question mark every aspect says authorized user accounts are not taken into consideration when factoring. So does AU accounts do anything at all?
They do. There are some that say that people shouldn't do that for an "artificial" score boost since it isn't your credit but that's an arguement for a different day. It will help as long as you're not applying for a loan like auto or a mortgage since manual reviews WILL remove any AUs from consideration.