Cooking (kitchen) Timer - Xtal or Resonator both too "slow"

[Acetronics2]

No, something else is affecting the oscillator's accuracy. But what is it?

On Interrupt Goto TICK_INT

How many times an Hour ???

BTW ... THIS

CalibrationLoop:
 LCDOut $FE,$8B
 If TMR1Cal=0 then
 LCDOut " "
 else
 If TMR1CalAR=0 then
 LCDOut "+"
 else
 LCDOut "-"
 endif
 endif
 LCDOut #TMR1Cal," "
 ' ----------------------------------------------------------
 ' Press Start Button to ADVANCE (speed-up) Clock
 ' Press STOP Button to RETARD (slow-down) Clock
 ' Press RESET Button to SAVE new Calibration Setting
 ' ----------------------------------------------------------
 ' Remember each Calibration 'tick' will advance or
 ' retard the Timing by 1uS in every 10mS period - that's
 ' 360mS/Hour per setting. Example: A setting of +8 will
 ' SPEED-UP the Timer by 2.88 Seconds (8 x 360mS) in an Hour.
 ' ----------------------------------------------------------
 If TMR1CalAR=0 then
 If ButStart=0 then Gosub CalAdvance
 If ButStop=0 then Gosub CalRetard
 else
 If ButStart=0 then Gosub CalRetard
 If ButStop=0 then Gosub CalAdvance
 endif
 If ButReset=0 then
 Write 0,TMR1CalAR
 Write 1,TMR1Cal
 LCDOut $FE,1,"Have a Nice Day"
 Pause 1000
 Goto DisplayReset
 endif
 SetupTimeout=SetupTimeout+1
 If SetupTimeout>200 then goto DisplayReset
 Pause 100
 Goto CalibrationLoop

has mysteriously disappeared from your code ...

Alain