⬆️ CC balance drops FICO 37 points, ⬇️ balance by same $amt one month later increases FICO 17 pts?!?

[rachelarmont]

I'm trying to rebuild my credit after a Chapter 13 last July. I'm up to 633 but I'm seriously beginning to question the weighted scoring used to define my FICO score, it seems skewed on the side of the creditors to justify high APRs. Example:

I had money in my savings to purchase a new PC. I decided to use my Capital One MasterCard so it would reflect responsible credit usage. I put the amount on my card which increased my balance from $38 to $1756. This resulted in a drop in my FICO of 37 points, but I figured it would increase more than that after I paid it off. Well, it didn't. I paid off the card entirely the following month, like I always do when using my card (I usually just use it for buying gas and pay it off when I get my statement). My score only increased by 17 when I paid off my card! Why did it have such a heavy negative impact when I used my credit but such a small positive impact when I paid it off the following month?!? It just doesn't make sense. I'm using my credit responsibly and getting penalized for it. I kept using my card for fuel after that and no changes have occurred to my credit in the 6 months since that transaction to make up for the -20 point difference. 

I'm beginning to think the three credit unions are on the take. Has anyone found a real explanation for this? I'm trying to toe this imaginary and ever-changing line that the FICO scoring uses and the line jumps around so much that any soft rules I thought were in place change radically from month to month and result in a skewed or distorted weighting system that only seems to benefit the creditors. 

Any help help or explanation would be appreciated. 

[Revelate]

We'd really need to see snapshots of all balances and similar to give you any sort of real idea; that you took a hit on the large purchase presumably changing your reported utilization markedly is expected, but revolving utilization is an instant in time measurement and certainly whenever I've done similar and then subsequently paid it off, I've recovered my points... but the rest of my tradelines are pretty constant in their balances so I don't get many vagaries there.  Also if your tradelines are mostly newer, there will be lots of small ups and downs for the first year or two which you'll be much happier if you ignore them honestly.

General advice: the biggest thing in rebuilding is to focus on making all the payments and never missing one.  Get a few open tradelines (which sounds like you've started with the Cap One card, muy bien!) and focus on the long term rebuilding from the CH13: I'd be the first to suggest FICO is setup for the lenders and isn't always in the consumer's favor, but it's not whimsical in it's scoring and changes to revolving balances are pretty well characterized by all the anecdotal information on this forum.