From FFXIclopedia, the free Final Fantasy XI encyclopedia

Level Sync Note

This item does not appear to work with Level Sync if the level is below its equip level. It gives 0 bonus to attack while wearing it. Tested at level 59 and level 50. Might be the same issue with all Ammo Slot "Stat Only" items. --Nuala Phoenix

I also noticed the -6 fire doesn't work either during level sync @50 --gojiso 01:21, 5 July 2009 (UTC)

Level Synced @60 with +1 to attack. Mortontony2 02:33, 28 August 2009 (UTC)

Just wondering, but ... this is stackable. Do the effects cumulate with more than one, or just the single effect? User:Kirol