Injector leak back test. Opinions pls

[Anubisxc70]

2004 XC70 D5 awd

Hello today i tested my injectors i number them 1 to 5 from left to right. After running for 1 min, the result was (photos 1,2 and 3) . The injectors 3 and 4 are the ones with different results. 3 has only a small amount and number 4 nothing??!!
After removing the tubes from the injectors all the diesel went to the bottles (photos 4 and 5). Number 3 almost catch up the other 3 , but number 4 didn't.

Any ideas? Is this normal (after all its less than 40 ml in a minute) or 3 and 4 are acting up??

Many Thanks

[Brendan W]

Post #2 is the kind of thing to be concerned about
https://www.volvoforums.org.uk/showt...+injector+test
Yours probably couldn't be better.