Is the number of zombies increased per plan you buy or how many players are on the server etc.? or neither? I have a 10 slot private server on PS4, and the population of zombies is pitiful, I swear there are way more on the public servers and there is nowhere to adjust this, is this just a calculated spawn ratio to players active on the server etc. or do the priv servers just lack the numbers unless you invest in the 100 slot server for a playerbase of 4? which is a bit of greedy money grab if that's the case
the zombies are usually based off of location. If you're in the city or towns there will be a lot more. It doesnt really have much to do with the amount of players more so your location on the map.