no way, he didnt mean to go through with condeming 100 souls. he was just buying time to get the key and the chest and save himself by destroying davy jones forever. Jack doesnt do things by halves. he was giving Will a chance to find the key, while he tried to find the chest. he had to bargain with jones to convince jones he wasnt up to anything sneaky, which of course he was.
yes Jack set 99 slaves free from the EITC (which are the people that live around Tia's hut, BTW, and thats why they mourn when they find out he died, cause he saved them from slavery) and thats how he got branded a pirate and his ship got sunk.
Davy Jones knew this and thats why he suggested 100 souls. Jacks + the 99.