The ingame tooltips for Dire Wolf and Grizzly say that Spirit Wolf gives a +25% Attack Rating synergy per level, but it’s actually +25 Attack Rating (flat AR) per level.
This can be seen in skills.txt under the “passivestat2” column for Summon Fenris (Dire Wolf) and Summon Grizzly, the affected stat is “tohit” which is for flat attack rating while the stat for attack rating% is actually “item_tohit_percent”.
This also applies to the Spirit Wolf itself, its tooltip states that it receives +25% AR per level but it’s just +25 flat AR.
Whether this is a tooltip bug or a skill bug is unknown, but I think it’d be fine to change it to Attack Rating%. Assuming that’s the case then it would be an easy fix, just change “tohit” to “item_tohit_percent”.