Our (Wife and I) FOID renewal letters showed up this year weeks apart, but our cards have the same date.
When we renewed our passports we spent extra money for mine to be expedited in case of a need for work, you pay extra and send the application priority mail as well. My passport showed up two days before hers and that was basically due to the expedited shipping, they shook me down for extra money to avoid a potential delay.
When we renewed our TSA pre they processed my app quickly without any further requirements, they made her go in for another interview.
I gave up trying to figure this stuff out.