eosio powerup ABI type is invalid

[pur3miish]

Description

On the eosio contract the powerup action ABI states net_frac: int64 cpu_frac: int64 stating that the data type is int64, however when interacting with the function from within the smart contract it requires us to use an unsigned integer uint64_t to power up, this has a discrepancy between working from within the smart contract and when serialising data type to send over RPC_URL.

I am looking for some clarification and the motivation behind this.