When you have small results in constituencies with few seats, comes a time when you have zero seat and waste all your votes.
I believe it's the case for BE: it has probably made its absolute decline even worse in terms of seats.
Yeah, especially with the D'Hondt method... Meh.
This post inspired me to calculate elections results if
Sainte-Laguë were used. I'll spare you the details, but the assembly will look as follows:
97 PSD (-8), 70 PS (-3),
26 CDS (+2), 20 PCP (+4), 12 BE (+4), 1 PAN (+1)
(Numbers in brackets note change from actual composition)
PSD/CDS coalition claims a majority of 8-12, depending on results of Portuguese abroad. The opposition gains six seats, though.