Guidelines are great
but they are just that. A few things to consider when deciding how much money to give for runs:
1) Additional income: Will there be any additional income? paydata? stolen gear? While this is meta information and not something Mr. Johnson can take into consideration, you as a GM need to keep this in mind.
2) Campaigns varies, some like gritty-we-can-barely-afford-soykaf campaigns with runners living in street lifestyles or lower and having to resort to organ legging to pay for ammo, other campaigns sports runners living in luxury, with private jets and stock portfolios. Well rounded characters with background stories and motivations beyond money for the next meal can generally "support" more cash payout as its not the motivating factor, but if your chars are more hollow, you might need to keep money low so they are forced to work. This also depends on the players, some NEED money to feel rewarded, others just see it as a tool to pay for Mr Friendly Troll Taxi driver contacts kids college.
3) How often do you blow up the characters vehicles, fry their cyberware, nullifies their fake id's, make their safehouses not so safe etc.
I don't think there is any "right answer", I think the most important part is so be consistent, start low, and slowly raise it as runners gain rep.
