This place is rated $$, but it should be $$$$. I tried to "Suggest an Edit", but the dollar rating wasn't available to change.
I'm not 100% sure, but I came across questions that asked contributions to google maps (local guides) that asked the $ rating of a restaurant. So part of it might be local guides wandering question about the place when google needs the answers.
If you want to show that they are and expensive or cheap place you can suggest an edit to add their menu which has there prices.
And if that isn't what you're looking for, you can write a review detailing the price range.
I did some research and was again like yourself unable to find a valuable answer! Although I did come across this thread:
I read through this but it appears it's just a bunch of people either guesses or creating some kind of rank for this system.
The one that seemed most likely to me was this post:
"They indicate whether the items on a particular restaurant's menu are inexpensive ($), moderately priced ($$), or expensive ($$$).
I believe those indicators are culled from reviews, so to a certain extent they would be relative to the area in which the restaurant is located. But keep in mind reviews are subjective. If a restaurant had two reviews and one person thought it was $ while another thought it was $$$, the actual listing would average them out as $$. "
If you truly feel this way about the business try leaving a review that mentions this and if that doesn't change maybe shoot google a message about the business here:
Hopefully, this leads you in the right direction! All the best ~Ethan