You're in for a big disappointment then, some time in the summer, on that day well known to politicians...a good day to bury bad news, you'll find that 18mths...now 12 left; that 12 will have suddenly become 36mths...or 48mths.I'm not even sure Allardyce wants to be here next season. He came out of semi-retirement to take the job. He spoke about the importance of spending time with his family at this stage of his life. It wouldn't surprise me if he sees Everton as one last short hurrah/payday and to bow out on a high at the end of this season.
I doubt he would want to end his career being a sacked Everton manager so all in all I'm expecting him not to be here after the last ball of the 17/18 season is kicked.
I really hope you vault me for being wrong, but I can see it happening.