I think it primarily depends on coaxial cable length. i.e distance between LNB and STB. More distance might cause delay.
Not at all. Cable Length has no consequence of time taken for transmission of signals from Dish to ur STB. If cable is longer though u would notice some decrease in signal strength / quality as received at ur dish vs on ur STB. Also as i have said do not go by signal readings on STB, these are at many times inaccurate bcoz of hardware/ software difference across STB models, one needs to check it using analog or digital signal meters to know actual reading