MSP430G2553: Code example in SLAA196 for HDQ, timer continous mode doubt

Part Number: MSP430G2553

Good day,

//------------------------------------------------------------------------------
// void HDQBreak(void)
//
// Local function to send a HDQ break-transmission for providing a safe
// communication start.
//------------------------------------------------------------------------------
static void HDQBreak(void)
{
                    TACCR0 = TAR + tBreak * 2; // Use double break time
                    TACCTL0 = OUTMOD_0 + CCIE; // Reset OUT0, enable int
                    ISRMode = imDelay; // Set ISR mode
                    LPM0; // Wait for ISR completion
                    TACCR0 += tBR; // Break recovery time
                    TACCTL0 = OUTMOD_0 + OUT + CCIE; // Set OUT0, enable int
                    LPM0; // Wait for ISR completion
}

I do not know why in the code above, use in the register TACCR0 twice the value tBreak to count. 

The timer is declared as SMCLK dependant and Continous mode.

Thanks.

ANDRÉS FELIPE RODRÍGUEZ