I thought I just make a suggestion for this. Happens to me a lot. 

So the time is about 2:14 and the clock is running down for a possible drug time change. For people who have slow internet like me; you ussualy wait a minute. Then, the time changes to 2:15 changing the drugs. 

EX: 

2:14

Heroin - 24 8,600

Coke - 4,900

You sell the herion, but you wait a moment for the internet to work. By the time it's 2:15

2:15

Herion - 6,755

Coke - 7,344

Then, you just wasted another moment of your time until you can move. 

I was thinking that you should have a Buy/Sell button on picking on both numbers to sell and buy quick. Trying to word this right. Sorry for being so difficult to understand at times. If any questions or further explanation. Please say something.

I'm struggling to understand your suggestion Sweeney.. Correct me please if I have picked it up wrong;

Are you suggesting the options allow you to do both actions at once, I.e. Sell coke and buy Heroin? Thus completing it all in one transaction?

Yes. That's what I meant. Sorry; me trying to explain things are not the best combination. Haha.