Talk:Expedition/Introduction/@comment-176.189.133.130-20160520174232/@comment-24930367-20160520174657

From Akashi Arsenal page:


 * Landing Crafts and Special Amphibious Landing Crafts improvements give a linear increase in Expedition Bonus, in addition to their original bonus. The bonus does not count toward the 20% bonus cap but only stars from first four of the fleet would be considered

Bolded part ought to answer your question. First four only, so no 22.5% in your case.