Even in 4.5.4 with a focus on horde maps, still the point breakdown system is bugged when you lose the control over the wall, you get more points when you should have less points (at least still on Minas Tirith on hard). But I give up reminding it, that is the last time.
I just tested it multiple times and this is NOT the case.
You get more passive points after a fixed time, I think this happened to you.
Can you give a replay?
Just to be a bit more clear of what I mean:
On hard you get 2 points per second.
After defending 480 seconds you will get 4 points per second.
After 900 seconds you will get 6 points per second.
After 1400 seconds you will get 8 points per second.
Those points are independent on controll over the wall or gates.
In addition to that you get the following points:
4 points per second if your wall stands
4 points per second if your main door stands
4 points per second if both secondary gates stand.
As an example the script for the wall points is:
*** IF ***
NOT Counter 'GG-FirstWallCounter' IS Less Than 1
*** THEN ***
Counter 'GG-Points' , Add with counter 'GG-PointsCounterAdd2'
"GG-FirstWallCounter" is the counter which is shown (starting at 100, going down).
So it is rather clear here: If the counter is not less than 1 (so if the counter is equal or above 1), the points are added.