A “tier” is defined as the individual distribution layer. Each tier consists of a walletlist and the corresponding distribution percentage and a tier limit(Only for Ether).
In a multi-tier distribution path for ether, the tier limit indicates the max amount of ether that can be distributed using the given walletlist and its corresponding distributions.
We support multiple tiers only for ether distribution currently.
ERC20 can only have a single tier, multi-tier will be released in future versions for this.