Is this issue a bug

[ElAguila64]

I have noticed a peculiar occurrence while playing. If I don't use any shooting nor explosive plant, much fewer zombies come out .If I use a shooting plant such as the electric peashooter and put it in turbo mode, I get a lot of zombies coming at me and I can usually score around 400,000.If I change and use just the wasabi whip and the iron spikewed and put it in turbo mode I don't see even half as many zombies so I can't score more than around 100,000. Why is this happening? Does it happen to anybody else?

[eieio_31310]

I do not think this is a bug. 

The zombies are coming out in batches, The weaker ones first then followed by stronger ones. 

The more quickly the weaker ones are killed from the start, the more stronger and nastier (and of course give you higher points) ones are followed.