Math IA SL

My teacher is saying that he's automatically downgrading us 2-3 points from criteria B (Mathematical communication) if we don't use HL concepts. He even told my friend who used HL topics that he'll still downgrade her at least one point because its still "not the most complex even HL wise". Is this fair??

In my IA I'm trying to compare sinusoidal functions. I basically have one ideal wave and am trying to compare 3 other waves to it and find which one is closest to the ideal. I tried looking for math HL topics on this but couldn't. I used two methods in my IA and was asked to change one but can't find anything complex enough.

P.S. I'm math AA SL

Edit: thank you to all the ppl who pointed it out that I confused criterion B and E, you're absolutely right I meant E I'm very sorry 😭