俱舍論記 14.59

14.59

「有覆無覆至逆追成者」者，釋下兩句。二無記表無成過、未，法力既劣、得力亦微，是故無能逆成未來、追成過去。

Regarding "Obstructed and unobstructed... retroactively possessing": this explains the lower two lines. The two indeterminate manifest karmas are not possessed in the past or future; since the power of the dharma is inferior, the power of acquisition (prāpti) is also weak, and therefore they cannot anticipate the future nor retroactively possess the past.