Sorry Les, I was writing when you posted. I get the same answer as you.
I am assuming you see how this is calculated: [1/(250000/4/8)]*23435=3S
1) Your oscillator is at 250,000 Hz
2) Instruction cycle is Fosc/4
3) Bits <4,5> of T1CON set a 1:8 prescale
Therefore each count = 1/((250,000/4)/8), which can also be written, 1/(250,000/(4*8), = 1/7812.5 =128 us per count. Then 3 seconds = 3 s /(128X10^-6) s/count = 23437.5 counts. The integer value of that is 23437 coounts.
Is there a small adjustment for code overhead?
0xFFFF - 0xA473 = 0x5B8C = d.23436 . It rolls over at 23437 counts.
John