I have a River Raisin R/D Longbow marked 57# @ 28". It shoots a 27" long 2018 arrow like a dart. The arrows have a 140 gr field point and 3 4" feathers. My draw is 26". Just for fun I punched in the numbers into the caculator and ended up over 10lbs difference. The site suggests only a 2lbs difference to start. Did I do something wrong or is this difference common? Again the 2018 shoot great and im not sure I want to change just curious. Thanks for the help.
I've notice a couple of things. I could get excellent arrow flight, but not have the arrows go where I was looking. I don't know, but maybe you have adapted to them shooting R or L.
Also had excellent arrow flight AND had them go where I was looking until I put broadheads on.
The calculator is pretty much on where I have a problem is deciding how much is center cut.
Bowmania
The calculator is a starting point. It can't take into account the human factor. I say that and I'm acutely wrong. There is a place in the calculator so that when you get an arrow flying great but it does not match you can plug in a number (form factor) and from that point on you can use it to keep you bow tuned or tune other bows to your form.
As to your question, if they are flying great with field points and broad heads don't change anything.
You didn't state what your Personal Form Factor is. Using Stu's calcultor and my 2212 arrow, with my 42# recurve, I have a Personal Form Factor number of (0), but with my 37# bow, I have a Personal Form Factor number of (9).
Like someone else said, if your 2018s are flying great, hit where you look with both field points and broadheads, stick with them.