Remember: this Coding is a transaction and not a Bunch of Lines.
"The imported amounts are a daily summary of the transactions for each account,"
AR = unpaid sales by specific customer names. If you are trying to manage Open balances generically, that is an Other Current Asset and not AR. AR requires this to be an invoice or statement charge, for that specific name and any payment needs to also be for that specific name and only the interface can be used to Apply them to each other.
"so things will always balance,"
Things Have to balance, or the coding is not valid.
"however it results in transaction overlap"
Your Snippet doesn't even include Transaction Type at all. Did you not include that here, or overlook it entirely?
"i.e. two or more cash deposits returns a single amount. Because of this the only way I can export to .iff is have a single transaction per day."
You can have Multiple Transactions. Each transaction has a Date.
"Will Quickbooks Premiere accept an .iif file that, for example, has positive values for AR and Cash, and the other balancing negative values?"
The coding you showed is Invalid.
You want to go back to your .iif kit and look at the "TRNSTYPE" Header options. You seem to want to do Daily Sales Summary = Sales Receipt = "CASH SALE" on the TRNS line, which is the Ending Amount (perhaps to Checking, as a Positive Number). Then, Split lines SPL to sales account = a Negative number for amount, assuming you are not also including qty and price. Otherwise, QTY is negative, Price is positive, and Amount ends Negative (is that math). Sales tax is negative, as well.
Other Asset is treated as a Payment, showing that Sales was not totally paid; all Payments would be Positive, if you are listing them to control the data flow manually.
$600 of sales (listing negative for the SPL = Credit to income)
$400 Put into a Charge Account (other asset) to be Paid later = positive to Other Current Asset (debit)
+ $350 as payment on account to clear earlier Other Current Asset = negative to Other Current Asset (credit)
Should = a Total on a sales receipt TRNS line of (600 minus 400 + 350) = $550 Positive on the Very First Line = TRNS, posting to Checking.
If some of that is still in the Safe, then you make a SPL line with Negative to "safe bank" for the amount Held out of this deposit to checking.
And if that is the Only activity you ever had in this file, then the Other Current Asset account now shows a running balance of $50:
I hope that helps.