Calculations On Properties, need understanding

I am trying to learn about this investing and forclosure as well as wholesales and FSBO when making an offer, could someone give me some advice, I am still learning, and I want to make sure I get this correct:

When going into an offer I will need to always multiply 70% to the ARV and then subtract my fees and then make the offer, is this correct, thanks

The 70% rule is a generic rule but that doesn’t work for every property. Here are the rules I use depending on ARV value. If wholesaling you would also need to subtract your fee from the final number.

More than $5,000 in repairs

ARV Less than $70K = -$20,000 - repairs
ARV between $70K and $140K = 70% - repairs
ARV Over $140K = -$40,000 - repairs
ARV Over $200K = 80% - repairs

Good condition(less than $5,000 in work)

Less than $400K= 85% - repairs
Over $400K= 90% - repairs