Help. Speed not matching in TMA

[Siinji30]

I´ve been doing lots of quickmissions just for training. And I ran into this weird problem just now. Can somebody explain.

I was tracking this sub, and with the DEMON I calculated his speed to 4 knots, and with the TMA i figured his range would be approx 4000 yards. But when I used SHOW TRUTH his range was about 10.000 yards. Then I went into the TMA to see what I had been doing wrong. But to my surprise I saw, that there was absolutely no way the I could have figured out his range. I had "locked the speed" at 4 knots (which was right, according to SHOW TRUTH), but the LOB´s had WAY too much space between them to match my TMA-ruler. The ruler´s measuring dot´s where too closely placed. If he was 10.000 yards out, he should have been doing more than twice the speed of 4 knots.

How can this be?

BTW, all this measuring lasted about 20 min. gameplay-time. I had made course changes from 000 to 030 to 090 to 270.