Eaydth also tells them the bigger the difference the more deference is required and that its new sisters who step into this problem most often because they have to figure out where the line is for each individual sister. This also implies that they need to figure out how much they can order another Sister around when they are stronger. We never see an instance where 1 or 2 levels creates more than a small amount of deference (stuff like letting the other woman voice her opinion first, or waiting until the stronger woman sat before seating yourself). It's only when a woman is at least 4 levels stronger that she seems able to give orders and 5+ when she gives orders that aren't even phrased as polite requests. Certainly even a tiny difference in training or age will help two women navigate the pecking order between them, but there needs to be a pretty good strength gap before one woman is clearly in charge of others.

Temaile was 17 and Eldrith 16 ... But the very fact that they were arguing over deference proves the point that only 1 level doesn't require much beyond social nicety. Even Liandrin didn't order the others around all that much and she was 3-4 levels higher than most of them and placed in command by the Supreme Council and/or Ishamael