[css-grid] sum of fractions < 1

After the recent change[1] in Flexbox that flex factors should be treated
as percentages when their total sum is less than 1, I'm wondering about
the corresponding case for Grid.  If the total sum of fractions in a track
is less than 1, should they be treated as percentages?

http://dev.w3.org/csswg/css-grid/#fr-unit
(the Note there seems wrong at the moment)

Cheers,
Mats

[1]
http://dev.w3.org/csswg/css-flexbox-1/issues-cr-2012#issue-30