explain rule 2 teamattack

[Pirkio]

Ok Rule 2 of teamattack says you are allowed to attack with 5 riders every 20 km's.

But don't explain when this 20 km's are counted.
What I mean?

I attack with 2 guys at km 1
Than other 2 guys at km 8
and 1 guy at km 15

Than I attack again with 2 guys at km 22
Other 2 at km 29
And another one at km 36

This seems to be fair because I've attacked alwais with 5 guys in 20 km's.

But the rule can also be read in this way

2 guys attack at km 1
2 at km 8
1 at km 15 (20 km start now)
When I attack at km 22 only 7 km passes.

Please explain me what is the correct way (or change it if you prefere one of the two)

[Hansa]

you attacked nowhere with more than 5 riders in between of 20 km so it should be ok
thats my oppinion of the rule