https://ficoforums.myfico.com/t5/Understanding-FICO-Scoring/Installment-loan-Utilization-affect-on-M...
https://ficoforums.myfico.com/t5/Understanding-FICO-Scoring/installment-loan-scoring-question/td-p/5...
https://ficoforums.myfico.com/t5/Understanding-FICO-Scoring/Installment-loan-utilization-in-mortgage...
some potentially useful threads, although I haven't read them too closely
you can try messing around on google with various searches such as:
installment utilization mortgage scores site: forum.myfico.com
installment utilization site: forum.myfico.com
etc.
@1t2b wrote:So we've followed the utilization rate idea where every time you get into a new range w/ individual cards and/or w/ the aggregate CC balance, you can expect to see some sort of increase. If I recall correctly, the % for these score increases are: under 88.9%, 68.9%, 48.9%, 28.9% and 8.9%.
Am I misremembering this? I can't seem to find the thread that discusses this, I thought it was pinned but haven't found it. Anyway we're buying a house in short order and I made several payments just to get them to the next bucket/range and while the regular credit scores are increasing, I'm not seeing any change in the mortgage scores at all. Another strange thing is that credit agencies (TU, Ex, EQ) that have for months reported on or around the same time are suddenly, this month only, not reporting at those times. It's like the universe is out to get us now that we're finally ready to move forward.
Thoughts or experiences?
1. No one really knows about revolving utilization thresholds. If you're talking about individual account utilization my experience teaches me that below 50% and below 30% are important thresholds.
2. If you're talking about aggregate utilization my experience teaches that there are no thresholds, just the lower the better.
3. The posts which gave you all these thresholds were, in my judgment, faulty in their methodology, and based on inadequate evidence, or in most cases no evidence. People jump on things like that because they would love to have that kind of certainty.
Since you're applying for mortgage scores my advice would be have as many zero balances as possible. Optimum would be all but one account reporting at zero. Also you should try to eliminate high utilization accounts. E.g. if you have some at 50% get them under 50. If you have some at 30% get them under 30.
Individual tradeline revolving utilization thresholds are scorecard and model dependent as far as anyone has been able to determine, we've seen a lot of diverse data.
On a dirty file I only found one individual threshold which basically amounted to "maxed out trade line." My own data was above 90% on EQ FICO 5 but some common wisdom from back in the day said 80%. I'm personally dubious on individual tradeline utilization having many thresholds and the common graph always had an "example" caveat. I really despised that picture for all that I respected the author 
.
Aggregate utilization has a handful of breakpoints from other reports but end of the day lower but non-zero utilization better and it doesn't need to be more complicated. Getting out from under most revolving debt is goodness regardless of score impact.
Grin, losing 50 points for 4 inquiries, illustrative indeed hahaha.