I believe it is a fiscal year thing...
For a one-time benefit, the time-honored tradition of being paid every 15th and the 30th was changed to 15th and the 1st in 1987. So, on pay period was effectively moved from 1987's budget to 1988 on October 1st, 1987. This helped the government at the moment.
What also helped the government was when the January 1, 1988 check was issued on the 31st of December (because of the New Year Holiday--wink, wink, nudge, nudge, say no more).
Unless the contract stipulates a time frame, getting paid after successful completion of the nuclear power pipeline can be up to termination. The weasel in me says they can justify reporting to the first sea-going command as an integral part of that successfull completion.
That's why everything must be stipulated by contract...