Flipping Homes & 70% Rule Questions!

So I have been a Realtor in the Myrtle Beach SC area for about 5 years now. I have been wanting to start doing some flips as well as acquiring rental properties and I have been doing a lot of research first. I don't really have any questions about rentals but for flips, I'm coming across some problems.

I use the 70% rule to evaluate max offer price. When I go to the foreclosure auctions or bid on any properties, I'm usually outbid and it's usually by over 10k or more making me feel like the 70% rule doesn't apply to my market. I don't know if I'm just over estimating repair costs or if I'm just missing something.

As a realtor, I know my ARV is spot on that's the easy part for me. But I feel like I'm missing something. I did hear of another rule that said take the ARV x 90% to take out holding costs, then subtract repair costs and the profit you want and use that as max offer price. Has anyone used this rule?

I just don't want to lose money on my first flip. I have found a condo in my area that is a perfect flip but my math says I need to get it for $65,000 max and the property is listed at $115,000 and the ARV is $128,880. I just know if I could get this for $65,000, it would be gone already so I know I can't get it for that price. I'm assuming 25k in repairs.

I doubt I'd get this under 90k so I'm struggling to make the numbers work to actually obtain the property. Any ideas would be greatly appreciated!!!