1. I believe no more on charge for the v 4 release ;)
(you can as owner of the v 3 use the beta v4 till the release )

2. you can use an another Dimension Plugin by Max Smirnov
if the native is not yet sufficient for you!
http://moi3d.com/forum/index.php?webtag=MOI&msg=7403.133

Here in French but the original is in English! ;)

You can dimension in 3D !