Hey so I haven't formally tested but short answer is more points into levitation mastery simply doesn't yield much more damage to be worth it really. You could max it out instead of Consume but I think Consume is better. Consume is also a synergy for hex bane so it helps your magic damage.
You have a few options really even beyond lev mastery and consume. There's also more points in sigil: lethargy, or more points in hex: bane or even hex: purge. Many options but yea here is bit of a breakdown for consume vs lev mastery:

lvl 1 consume + +skills = lvl 18 (without BC) = +22% max life, and 1170 max magic dmg of hex bane (without BC)
lvl 20 consume + +skills = lvl 37 (without BC) = +41% max life, and 2064 max magic dmg of hex bane (without BC)

vs.

lvl 1 lev mastery + +skills = lvl 26 (without BC) = +125% damage, 31% crit, -50% weapon req
lvl 20 lev mastery + + skills = lvl 45 (without BC) = +201% damage, 33% crit, -50% weapon req


So yea there you have it, consume gets you more life and magic damage, whereas lev mastery would get you more phys damage and 2% higher crit chance. The way lev mastery's +% damage is applied I think is similar to the +% damage you get from auras and gear... it's prob just added on all that which is already a ton especially if you use phoenix but regardless. Like I said, haven't formally tested but I don't think it would add a ton of damage because it's not increasing the BASE damage like echoing strike points and its direct synergies do. Moreover 2% higher crit chance after investing 19 more points just seems like a poor return on investment. therefore, Consume is my pick.

fyi if you put the 19 points to max out hex bane instead of consume, its max magic dmg would be 2871 (without BC). So 2871 vs 2064 & 19% more life bonus with consume. I figure you're already doing plenty of damage, it's nice to have some magic damage mixed in there but I thought 2064 was enough vs the 2871 as I'd rather have a bit more life. Also I liked getting more duration for Consume as well (760 seconds maxed vs 380 seconds not). Consume is a bit more annoying to recast than hex bane is so yea.

I liked the looks of blood oath a lot to max until found out apparently it's capped at 40%. It has other benefits but still that was the main one so yea.

Anyway you really can't go wrong with whichever route you want to take, whether you want more phys damage with sigil lethargy or lev mastery, more magic damage with a hex, or more magic damage and life with consume. It's up to you

100% Chance To Cast level 40 Blaze When You Level-up
40% Chance To Cast Level 22 Firestorm On Striking
Level 10-15 Redemption Aura When Equipped
+350-400 Defense vs. Missile
+350-400% Enhanced Damage
-28% To Enemy Fire Resist
+50 To Life
+5% To Maximum Lightning Resist
+10% To Maximum Fire Resist
+15-21 Fire Absorb

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