It’s three months salary plus, prorated bonus.

Source: https://www.nnsl.com/business/nwt-chamber-of-commerce-diavik-digs-deep-to-reward-workers-who-stay-on-until-closure/

So, in the FINRA example from the intro, the $6,500 difference between what you paid for the zero-coupon bond ($3,500) and what was received at maturity ($10,000) is taxable in 20 prorated annual amounts of $325.

Source: https://investorplace.com/2023/08/supercharge-your-ira-3-reasons-why-treasury-strips-could-be-your-next-smart-move/

The costs of each SRO are prorated for the 191.25 days officers would be working in the schools and not handling work outside of the school system.

Source: https://www.lagrangenews.com/2023/03/18/tcss-approves-sro-agreements-with-local-cities-and-county/