俱舍論記 8.68

8.68

「既爾中有至說名中有」者，更作好解。名中有故，不應名趣。二趣中間而受生故，名為中有。此若趣攝，不應名中。

"Since this is so, the intermediate existence ... is called the intermediate existence" provides a better explanation. Because it is called the 'intermediate existence', it should not be called a 'destiny'. It is called the 'intermediate existence' because it takes birth in the middle between two destinies. If this were subsumed under the destinies, it should not be called 'intermediate'.