Of course it's the same.
You tell the compiler: "Look, the LCD controller I have connected needs 35us to process data and 900us to process commands, please give me code for that". The compiler will give you code for that, making sure that it gives the LCD controller 35us to process data and 900us to process commands.

Running at 4MHz* or 64MHz makes no difference, each datatransfer WILL take 35us and each command WILL take 900us because that IS what you, the programer, have told the compiler that you WANT it to take.

I can assure you that if run:
Code:
LATB.0 = 1
arraywrite topline, ["SOMETEXT HERE  XXX"]
LATB.0 = 0
and

Code:
LATB.0 = 1
LCDOUT $FE,$80+i+c 'UPDATE Y POSITION
LATB.0 = 0
at both 16MHz and 64MHz you'll be able to measure a considerable increase in speed on the first but very tiny on the second (because, as explained, most time spent executing that statement is spent doing nothing).

* At 4MHz it MIGHT not be able to stick to 35us, it MIGHT take slightly longer, I don't know for sure.