1 extra flight but less points required?

[Amanad78]

Hi, can anyone explain the following please?

LHR-CDG 16 Apr (BA)
+
CDG-DOH-ADL-BNE 19 Apr (QATAR)
= 151,200 points + £585 for 2 pax, economy

If you discard the LHR-CDG leg:
CDG-DOH-ADL-BNE 19 Apr (QATAR)
= 156,400 points + €620 for 2 pax, economy

I don't understand, same Qatar flight minus the UK to France costs more points??

Thanks