subscribe by email plugin cron job

Hi there.

Running the Subscribe by Email plugin together with the mandrill plugin that allows me unlimited emails per hour sending. All working well.

Currently about 12 000 subscribers, plugin settings set to mail 10 000 every 20min, normal wordpress cron job set to run every 15min.

Currently I'm sitting on day 2 and still have emails in the queue, about 600.

Is there maybe another cron job link for this plugin because it dont seem that the normal wordpress plugin cron runs it?