I had a similar idea as Henk as I started reading the post. If you can assign a unique serial number to a bot's venom/poison/etc. based on its species, memory target, and maybe a custom value, then you can allow for the creation of antivenom/antipoison without underpowering venom and poison.
The easiest method would be a one-to-one deletion of venom for antivenom. If you have 30 antivenom that is keyed into a specific value (ie: protein marker) and I shoot you with 40 venom, then you lose 30 antivenom and get 10 venom worth of effect.
That encourages the simoltaneous buildup of attack and counter that we see in nature (I forget what it's called, but it's basically like how the US and Russia kept building more weapons. It's a mutual escalation that doesn't actually change the individual positions.)
The same idea could be applied to all attacks and defenses. A -6 shot that matches the target bots body serial would be useless (good for conspec immunity). If your shot matches a shell's serial, it could pass right through unhurt (a sudden leap in evolution for the attacker. Suddenly it can eat hundreds of times easier than its compatriots.)