Forwards - Mark to Market Formulas different in Kaplan vs CFAI

Looking for some clarity here. I am studying using Kaplan/Meldrum w/ CFAI problems.

The mark to market formula for a Forward seems straightforward.

For Kaplan - (FPt-FP)(contract size) / (1+R(days/360)) = Vt

FPt = Forward price at time t in the market

FP = Forward price specified in the contract @ inception

R = rate of price currency

Vt = value of forward at time t

For CFAI/MM - (FP - FPt)(contract size) / (1+R(days/360)) = Vt

Notice the difference in FP and FPt…it seems like Kaplan is referencing BUYING the base. CFAI/MM is referencing selling the Base?

In other words, when you buy the base, its FPt-FP and when you sell the base, its FP-FPt? I haven’t seen a clear rule outlined in either text for this.

Thank you.

It’s more common to calculate the value to the long position, suggesting that Kaplan’s formula is more common than CFA Institute’s.

What’s important to you, however, is that you recognize that they’re different and why. You seem to have done that, so you’re good.

OK thank you.

My pleasure.