Measure distance along multiple points give wrong result

Hi, 

I'm trying to measure distances along pipe runs with bends. I have tested this on a straight pipe and TrueView is giving the wrong results:

I measured a straight pipe run as 3866 mm

I broke this down to two sections and measured these individually as 1835 and 2031 mm

So far so good. 

But, when I measure the 3866 mm in sections using the "measuregeom > multiple" command, Trueview gives the first distance as 12.23 and the total distance as 25.77. 

I have included a screen shot of the output dialogue below. This isn't a problem for straight pipe runs, but is for measuring pipe runs with bends about a site. 

Many thanks, Chris