回複：請問H1從大學轉到公司是不是4月申請,收據到了就可以工作

I think that you can do it. None of the AC21 related memos I have read mention that a quota will prevent you from using H-1B portability provision. Once your application is accepted by CIS in April, I believe that you can jump to the new company. Ask the company lawyer for a clarification.