I HATE MATH...  Im trying to figure out if the formula that i am using is wrong and which is more accurate...

So im trying to figure out how the 70% rule makes sense, by attempting to break down the numbers.

So the flipping formula is ARV-Repair costs- Closing/Holding costs-Profits= Max Offer

ARV-200k

repair costs- 0

closing costs on both sides..  buying closing costs 5%

                                                    selling closing costs-  agent- 3-6%  (we'll say 4%)

                                                                                      title escrow- 1%

                  So purchase and selling costs together = 10%

Holding costs-Hard money mortgage-  8-12%  (we'll use 12%)

                          property taxes               2%

                           Insurance                      .5%

                          maintenance                 -0%

                           utilities                           .5%

so all of the holding costs = 15%.

So if i add closing and holding costs together thats = 25%

so 200k arv  - 0 repair costs  - 25% closing costs and holding costs  -  25k profit = my max offer of 125k.

If i do ARV- repair costs- 70% that = 140k.

Did i mess up my numbers above? which one is more accurate