No, Lysimachus, the 6 extra trebuchets just drain your treasury. They're too far away to be useful and cost 15,000 florins before you get them near enough to use them. Also, very few cities/castles will have balista towers when you get there so that 's not a problem. Two trebs in a stack will knock 4 holes in wooden walls or 2 holes in stone walls without a problem. Then, simply march your Mongol infantry up to the openings and shoot the garrison units as they stand there. (That is a problem caused by CA's programming) You'll lose a few men, then send in your cavalry to clean up.
Three stacks are all that is needed to clean out the Kwazzies but you've got 11

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