Dispute causing score drop?

[myfico5378]

I recently submitted a dispute to TU for lates that were showing on accounts IIB almost 6 years ago.  Myfico didn't show the lates, but when I pulled my TU report from TU they were there so I disputed.  Other than the lates, the accounts were being reported accurately (i.e. DOLA and IIB). 

I happened to look at my TU score on WAMU today and noticed it was down by 100 points!! So, I went into myfico to order an updated score to see what was really going on and it was down 65 points!  It said my most recent late occurred 2 MONTHS AGO! What the??? I haven't had any lates? So, I started looking through the accounts that were flagged which were the 5 accounts IIB and one of them has been updated to say account closed in April 2008, but I noticed that it was that way on my last report too.  It doesn't show any lates anywhere in my report, but it must have something behind the scenes since one of the factors affecting my score was a recent late. 

Next, I went to TU and checked the status of my dispute.  It says 3 of 7 items are completed.

Has my score just dropped because I initiated a dispute?  Why would it show that my most recent late occurred 2 months ago in the explanations, but not have any record of any lates on any of the accounts?

[llecs]

There could 2 things happening or a combination of these 2 (due to disputing 7 accts):

1) Disputing could cause account(s) to update. On the the side-effects of disputing is that an account could update so as to appear as new in your reports. FICO reads that as a new baddie and causes your score to drop. Once things finalize, take a look. There could be an updated late if a CA or unpaid CO acct.

2) Also, for TU and EQ, disputing will remove that account from the FICO formula for scoring purposes. That account may still be in your report, but FICO is not reading it. Maybe you disputed an account that was helping more than hurting. Remember, you can actually remove an upaid CO and see a score drop!

After the disputes are finished, your new score will reflect any change.