I call it randomness and chance of success repeating itself. No matter what you may call it, there seems to be a force behind combining and upgrading weapons. Yesterday I combined a Fine field lance and an intense one to create a type C Pain Intense FL. I maybe a warder but there are certain times when you just need to pull out that two-hand weapon to swat annoyances called fleshlings. So I combined those two FLs along with a type C black excelsiar and got what I wanted in one process. I socketed the PI FL upto +2 with no problem but when I attempted to upgraded it to +3 the Keen talics were wiped out. Level 50 Punisher FieldMarshal comes to the rescue with his +5 Intense Hora Spear in hand. I handed him my PI FL and he gave back a +3, wasting only 2 sets of high gems and keen. Take note that he upped my Intense 47 Melee Head to +4 just the other day with one process. The spare +3 was sadly destroyed by yours truly. FM asked me if I wanted to go for +4 with my FL. I said I'll push his luck and my luck for next time.
(Pain Intense weapons provide the wielder with an additional 30 points of accuracy, great for those pesky dodging fleshies.)