odd speed reading

Hi guys,

I need your help.

I'm playing GWS SH4, and loving it, but for some reason when I calculate my target's speed through the perisocope notepad it will work sometimes - showing values of say 4 or 5 KTS for a merchant, but other times will show 45, 80 or 90 KTS values. What the hell?

Am I doing something wrong, or is this a bug.

Thanks for your help.