I haven't got scan to send you trim sheet.
Oh, well, never mind ... let's work out a Plan B.
When I compute UI for Hold 1 with Airbus data: Hold1 Harm = 12.283 m from Airbus Doc
As the station is forward of the datum (Ref Stn), the ΔIU has to be negative. For interest, my calculation gives
ΔIU = -0.006567 / kg
The third (Trim sheet) come from XL AirWay Hold 1 ==> 500kg = ~1,1 UI
Ah, now this presents a problem. Most likely, the IU equation is different.
I will try to scan the LOADSHEET and i will send it to you
This is fairly important as, without the pictures of the various sheets, I can't figure out where the error is.
i used electronic Loadsheet create by gaetan (airfrance software) to control my result
That's fine but, if we sort out the trimsheets first, then we have somewhere to start and can look at the software.
I found Aircraft manual about Boeing with Arm of Hold, can I use the same equation to compute Unit Index?
You can only use the same IU equation if the two systems use the same equation. The problem is that there is no reason for different loading systems to use the same IU equation and, very often, the equations will be different. If is essential to make sure that sheets are compatible before you start running calculations other than using the sheet and the declared entry data.