Stock trading question

[jmcoreymv]

I am currently using two different brokerage services, Scottrade and Ameritrade. My question is in regards to unsettled funds on a cash account. With Ameritrade if I buy a stock on 8/1 and sell it on 8/3, the cash is not available until 8/4 since Ameritrade claims the law says you cant have access to the cash until 3 days after the BUY. With Scottrade on the other hand, if I buy on 8/1 and sell on 8/3, I cant use the cash again until 8/6 because they say the law says you cant have access to the cash until 3 days after the SELL. So which is it, 3 days after the buy or sell that my funds become available?