I came to the dilution of 1+3 because i was experimienting. Also my water tap temp, which i was not checking at one point. I thought if it was warmer i could shave off a couple minutes depending on temp. which i wouldn't have to calculate exactly because of high dilution (laziness). When i began to control temp (68 deg.), i just kept the dilution. Also, i read good things about 1+3 dilution. When i began to check my process, i came across minimum developer necessary which i was not meeting. Reason for dilution may be for O/U mentioned below or affecting grain/contrast, i personally liked my results, and for the sake of some sort of consistency kept the dilution.
I also noted as i keep looking through apug history that what i'm actually doing is Overexposing + Underdeveloping, which i apparently like, as my scenes for the most part tend to be high contrast. This is why my 100ml is probably not developing my negatives completely and retaining highlights. IF you look up Overexposing + Underdeveloping you'll get lots of hits here on apug. And if you look up d76 1+3 you'll also get several hits. Most O/U threads don't mention exhausting developer through high dilutions, but 1+3 threads caution against possible exhaustion if not enough developer is used. I didn't realize what i was doing, but now everything is pretty clear.
taken fromYou can develop one 135-3 roll (80 square inches) in 473 mL (16 ounces) or two rolls together in 946 mL (one quart) of diluted developer. If you process one
135-36 roll in a 237 mL (8-ounce) tank or two 135-36 rolls in a 473 mL (16-ounce) tank, increase the development time by 10 percent (see the following tables).
Several people have noted that the REASON for minimum developer noted is for high key scenes, where say 100ml (as i use) tend to not be enough to give clean whites, etc. So while it might be enough for many occasions, it might not always fit the bill.
Thanks to everyone. I don't know if i missed something else.