That's fine. The Secondary applicant's experience isn't mandatory unless its a Canadian one. Its one's personal preference whether to claim this experience or not!
Note: You won't get any additional pts for the Foreign work experience of your spouse. However, if its under the Canadian Experience Class (CEC), then the pts can be claimed.
Some specific countries do not issue the PCC(s) without a request letter from CIC. Thus, a formal Letter-of-explanation (LOE) is required to be submitted into the respective placeholder mentioning the same.
Besides, you need PCC(s) only for those countries where you have stayed for a period of 6 consecutive months or more, otherwise not required.
You just need a single letter mentioning both the employment periods held by you in Company A. Even if the designation was different, a single document would have sufficed. You can mention these two periods in "list view/table or bullet points".