Doubt about CFxDEN calculations

Hi everyone!

I was following AN-1171 (Rev.A) to calibrate ADE7880 until I stop at:

(Page 8 of 16)

If you do the maths exactly as it appear the result is 3507.270118 (Rounded to 3507 = 0xDB3)

Now I take ADE7880 datasheet (Rev.A) to see if I'm missing something and I stop again at:

(Page 66 of 104)

Different way to calculate same register ... which one is the correct way? Why so different formulas?

I insist trying and use first equation result to calculate "n" with the second one and I get -5,05012018041. As datasheet says "(...)where n is a positive or negative integer(...)":

1. If I round to -5, CFxDEN is 31250 (3822 less!)
2. If I round to -6, CFxDEN is 312500 (277427 more!)

Its a big difference no matter which one I choose (i know I can adjust CF later but .. I want to establish a nice accuracy from base first)

Resuming, please throw me light over CFxDEN calculations!

Thanks in advance and best regards,

CieNTi

CieNTi: Added documents revisions and formulas pages for better reference