Confused in ref to increase and decrease

[CM23]

I'm frustrated and confused trying to understand this. I sit on the edge of my seat every day waiting for all 3 scores to increase so I may obtain a reasonable mortgage rate. Meanwhile, the home I chose is under contract with someone else because of my credit issues.

I was added as an AU to two accounts. The 1st one report to all 3 CRA and raised my scores minimum 40 points to 702, 682 and 671. All I needed was all 3 to be minimum of 680.. so obviously that 2nd AU hitting would be amazing. The 2nd one hits and it increases TU to 714 but dropped the other 2 by at least 20 points. Now I'm around 658-660. This line has 17k limit, barely 2k used and open for 3 years. I dont get it.

[rbentley]

The second account you were added to as an AU may have issues.  It could have lates or high UTL.

[CM23]

There are no reported lates and UTL is around 8%

[RobertEG]

Addition of an AU account is, by definition, the addition of the credit history of another to your credit file/report.

Even if the addition of the AU results in an increase in your credit score, that increase is not based on evaluaiton of your own credit history, and the potential creditor is not bound to consider that AU-affected score in their determination of grant of credit.

They can, and many mortgage lendors do, decline to consider any score that is based in part on the credit history of another.

It is common to request the consumer to first remove the AU so that the potential creditor can then obtain and consider a score that is based only on the history of the consumer that is requesting the loan.

If the potential lendor even considering the AU-affected score in their underwriting determination?

[CM23]

Adding an AU account was suggested by the lender, so no issues with this particular one. Thank you for your explanation and advice.