Here is my draft evaluation when old MCU replacement for power consumption, the comparsion betwween PIC and MSP430.

The current calculation is based on average of one bit-bang communication. One bit-bang communication total time is 48.868 ms, 28.868 ms for communication total 21bits, 20 ms for idle.

All current use the typical value.

PIC works in 1MHZ.  The working current without ADC is 2.7 mA at 4MH, the current of ADC without reference is 180 uA, the current of Sleeping is 1.0 uA.

Three times ADC sampling of each bit for first 13 bits. One ADC sampling will continue 6 us (0.006 ms).

(2700 uA x 28.868 ms / 4M + 1.5 uA x 20 ms + 3 times x 0.006 ms x 13 x 180 uA )  / 48.868 ms = (19485.9 uA *ms + 30 uA * ms + 42.12 uA * ms)/48.868 ms= 410.17 uA

MS430 works in 1MHZ at AM mode, the sleep mode is LPM3.

ADC is used too, 6us sampling time for each ADC too.

(390 uA x 28.868 ms + 0.9 uA x 20 ms + 3 times x 0.006 ms x 13 x 600 uA )  / 48.868 ms = (11258.5 uA *ms + 18 uA * ms + 140.4 uA * ms)/48.868 ms= 233.6 uA

In conclusion, MS430 is better than PIC16C715.