omen of whittling. something strange happened

https://imgur.com/h8q8OdE

i managed to get the bomb =)
i had exalted it with 35 energy shield and 13% armor. i used 2 whittling omens to get 172 life. what is really strange is that i first got 78 mana and then i got lucky, but mana on amulet is ilvl 82 so with the second omen of whittling why i was able to reroll mana instead of strenght (ilvl 74) or all res (ilvl 80) or life% (ilvl 80)?
i mean, i am super happy about it but wtf went on there exactely?

78 Mana on Amulet is T6 - ilvl 31 roll

oh, that's huge! then my ilvl roll on 35 energy shield is 37. if i hit that with another whittling omen i shoul have chance for a double roll on life or rarity right?