Why did my score drop so drastically?

[Anonymous]

Ok, so here is the background:

My score has hovered right around 725 (experian) for 6+ months.  I recently purchased a boat then a house.  Now yes I can understand the new accounts and use of credit that will cause the score to move.  I am just hoping someone can better explain why.

So as of July I had 3 credit cards (Chase, Chase, BankOfAmerica), 5 merchant cards (jcpenny, paypal smart connect, best buy, home depot and discount tire), 1 vehicle loan, 1 boat loan and student loans.  I previously had a boat loan and it was paid in full effective july 2014 (about 9 months early).  August 2014 I applied for a new boat loan.  I was approved and loan was generated for $94,500.  After purchase of the new boat, I paid off my vehicle loan to Ford Motor Credit 13 months early for $9300.  In late october I applied for a Mortgage and I was pre-approved, I bid on the house and won the auction.  Generated new mortgage for 72k after 25% down payment.  After all this my score went from 726 to 751 then again to 767.  A month later it dropped to 747 then to 724 10 days later. 

Now the mortgage inquires show on my credit but the new account has yet to show up on any of my reports, im assuming because the mortgage was sold before the first payment and the new lender has to process all the documents? 

All in all with the boat loan inquiry and the 2 mortgage inquiries (one initial and one day of closing) it took my total inquires in the past 24 months to 6.  I have cut all my revovling debt to zero.  All cards are paid in full within the last 30 days (obviously not enough time to reflect on report) but I am still curious as to why my score went up 40+ points then dropped more than it increased.

Never a late payment, no prior bankruptcies.  I am pretty knowledgeable on the financial end of things and how credit works but still lacking knowledge in exactly what dictates the score increase/decrease (other than the basics, late payments, deliquencies, foreclosures).

Thanks for any info, if I need to provide anymore info please let me know and I will update it!

[Momof5]

Aside from the new accts, you paid off an older acct.  You may have altered your AAoA sufficiently to cause the score drop.  Seriously, I *wish* I had your problem!

[Anonymous]

" but still lacking knowledge in exactly what dictates the score increase/decrease (other than the basics, late payments, deliquencies, foreclosures)."

Truthfully - we are ALL in the same boat. The fact is that the various FICO scoring models are complex mathmatical algorithms based on statistical analysis, the details of which are a closely guarded secret. We can make educated geusses based on score changes we can observe after specific limited changes occur on our reports, but they are still just geusses as we have no idea how the various items interact with each other. Things that have minor impacts like credit mix, and inquiries are particularly hard to predict when the report is very complex.