I can't tell anything about ADCOM As it doesn't exist, but let's try with ADCON0

If you plan to use PBP ADCIN, use my PicMultiCalc software. It make things easy. Let's say your OSC=20 MHz, your analog source impedance is 1K and you want to make a 10 Bit conversion, you need to add those DEFINEs at the top of your code
Code:
DEFINE ADC_BITS 10    ' ADCIN resolution  (Bits)
DEFINE ADC_CLOCK 2    ' ADC clock source  (Fosc/32)
DEFINE ADC_SAMPLEUS 3 ' ADC sampling time (uSec)
ADC_CLOCK 2 refer to ADCS1:ADCS0 bits (ADCON0<7:6>)

Sure you could even use the usual Frc and set your Sampling time to 50uSec and it will cover almost every possible situation.

Even by using the PicMultiCalc, you'll need to set the ADFM bit in ADCON1 register. Yeah i didn't include this in the software as Microchip change their mind in almost every new PIC. Maybe One day... maybe.