Electronic – C18 Timer0 timing calculation using MCC18

I am programming a PIC18F4520 and I've set it to use a 32Mhz internal clock.

I need a counter to tick every second so I'm using TMR0 for this purpose.

To use TMR0, I have set the following:

• Prescaler 1:256
• 16 Bit mode
• High level interrupt on TMR0 overflow.

To set the timer to count every 1 second, I've calculated it as follows:

TMR0 = (Required time)/(4 * Timer clock * prescale value)
     = 1 / (4  * (1/32000000) * 256)
     = 31250

So, TMR0 = 0xFFFF - 31250.

Is this correct? If not, what am I missing? The code is as follows:

#pragma code
void main(void)
{
    //Set clock frequency
    OSCCON |= 0x70;             //8 Mhz clock, primary clock
    OSCTUNEbits.PLLEN = 1;          //4x Multiplier, thus we have 32 Mhz clock
    while (!OSCCONbits.IOFS);       //Wait until INTOSC is stable.

    //Enable TRISA as analog input (For ADC)
    TRISA = 0x2F;

    //PIN Outputs
    TRISB = 0;              //Make PORTD as output
    //Reset PORTB
    PORTB = 0;

    //Set ADC
    OpenADC(ADC_FOSC_32 &           //Fosc/32
         ADC_RIGHT_JUST &
         ADC_4_TAD,             //4xTAD
         ADC_CH0 &
         ADC_REF_VDD_VSS &
         ADC_INT_OFF, ADC_5ANA);        //ADC CH0-CH4 Initialized

    //Set Timer0
    OpenTimer0( TIMER_INT_ON &
                T0_16BIT &
                T0_SOURCE_INT &
                T0_PS_1_256);

    //Write Timer
    WriteTimer0(CLOCK_TICK);

    INTCON2bits.TMR0IP = 1;         //TMR0 has high overflow interrupt priority
    RCONbits.IPEN = 1;                  //enable priority levels
    INTCONbits.GIEH = 1;            //enable high interrupts

    //Begin
    while (TRUE)
    {

    }

    CloseADC();             //Closing ADC
    CloseTimer0();
}

On my high level interrupt vector, I've done this:

#pragma code 
#pragma interrupt high_priority_interrupt 
void high_priority_interrupt()
{
    if (INTCONbits.TMR0IF)                  //TIMER0 overflowed
    {
        //Stuff
        second += 1;
        if (second == 60)
        {
            minute += 1;
            second = 0;
        }

        if (minute == 60)
        {
            measure_and_switch();
            WriteTimer0(CLOCK_TICK);
            minute = 0;
        }

        INTCONbits.TMR0IF = 0;              //Clear TIMER0 overflow bit.
    }
}

So, basically, every 2 minutes, I want the method measure_and_switch() to be executed. Should I follow it with WriteTimer0()?

Btw: CLOCK_TICK is TMR0 (calculation from above).

Thanks