I've had a bit of a play with a valorite runic today and it sometimes seems to only apply 4 mods.
I created a char with 120 smith and 100 arms lore, I made all double axes as I had a 100% chance to make it exceptional, and used gold ingots.
With this setup, all the axes should have atleast 40 luck and 50 lower requirements from the gold, and 40 di from being exceptional and GM arms lore.
Most of the axes had 5 mods, like the one below
Poison ele slayer
Luck 40
DCI 14
FC 1
SSI 25
DI 44
Lower requirements 50
But the ones below, look to have only 4
1.
Mage wep -20
Luck 40
HCI 13
DCI 13
SSI 30
DI 40
Lower requirements 50
2.
Spell channeling
HLL 78
HMA 44
Luck 40
FC -1
DI 40
Lower requirements 50
UBWS
3.
Spell channeling
HSL 44
Luck 40
HCI 14
DI 43
Lower requirements 50
4.
HLA 48
Mage wep -21
Spell channeling
Luck 40
DI 50
Lower requirements 50
5.
HLA 46
Mage wep -21
Snake slayer
Luck 40
DI 40
Cold resist 14
Lower requirements 50
6.
Spell channeling
HML 68
Luck 40
HCI 13
DCI 15
FC -1
DI 40
Lower requirements 50
7.
Spell channeling
HML 74
Luck 40
DCI 13
FC -1
DI 40
Lower requirements 50
UBWS
8.
HML 68
Snow ele slayer
Luck 40
HCI 14
DI 40
Fire resist 13
Lower requirements 50
9.
Spell channeling
Luck 40
DCI 13
SSI 30
DI 40
Lower requirements 50
All of the axes listed were 100% Physical damage.
I'm not sure how Spell channeling and fc works. #3 and #4 could have 5 mods because theres no fc-1, but #9 looks to have only 3 mods, or a max of 4 due to no fc-1.
I'm no great crafter, its not my main character, and my only experience with runics is a DC on Europa and when crafting on test to try out a template, so I maybe totally wrong here, or being blind, but if someone with more knowledge then me can check this out and let everyone know.