How are multiple 180+ day lates scored?

[RTOrockstar]

Ok, long story short(and I posted a thread about this over a year ago so no need for backstory):

Back in 2009 I co-signed on a loan for my ex-wife. She does pay but pays whenever she feels like. It is reporting 180+ days late every month(only reports to EQ). It was holding my score down pretty good at first but now my score is starting to reach the lower mid-600's so I'm thinking that it's not affecting my credit report as much now as it did in the beginning.

So without reminding me that I should never co-sign for anything, can anyone tell me how this is being scored now, why is it (thankfully)having less impact on me?

[guiness56]

As with anything else they age and with time affect you less.  180+ days late are the equivalent of a CO.  Once you are hit with that initial one, the rest are more or less an update of when it first happened.