Does not blockchain.info directly offer this API for multi-send ?
My thoughts exactly, what's wrong with just using the API directly?
https://blockchain.info/merchant/$guid/sendmany?password=$main_password&second_password=$second_password&recipients=$recipients&shared=$shared&fee=$fee
This script is intended to be used for callbacks.
The specific use case for the client who requested this script was to make a forwarding address. Specifically, where when a specific address receives a transaction, the amount is split and sent to multiple other addresses based on a percentage value. This whole process happening automatically and without delay (with the availability for confirmation delay).