User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-112.209.90.43-20130423232421/@comment-4411728-20130424031300

The slime number itself is how often the slime will build up. With bombadier the number will rise meaning you will build up the slime faster.

Not to mention, regular slime once it explodes will have the fixed damage of a large barrel bomb. With bombadier that damage will be a large barrel bomb+.

Hope this answers your question.