Do decision makers need to consider the time value of money when
evaluating transactions with cash inflows and outflows occurring in
the same period?

Sljames822 --

Financial budgeting typically simplifies a business model and assumes
that cash flows are even.  But there is a cost (or a profit) depending
on the cash balances.  Indeed corporate financial managers today even
sweep cash balances automatically into overnight deposits to earn
extra money on "repo" or "repurchase agreements" --

Investopedia
"Repurchase Agreement"
http://www.investopedia.com/terms/r/repurchaseagreement.asp

Ideally, you'd set up every problem on a daily basis -- but the
complexity would be overwhelming.

There are multiple examples of situations where a rough financial
model assumes certain payments are made in the same period -- but a
cash manager would have to borrow money (perhaps at very high
short-term rates) if cash flow weren't positive:
*  we generally assume taxes are paid annually at year-end, when in
fact the corporation pays them quarterly
*  in a rental situation you would probably set up income &
maintenance as annual line items.  However, treating them in the same
period ignores the fact that rents get paid monthly -- and timing of
maintenance expenses during the year would be very important.
*  payment of dividends on bonds is typically calculated on an annual
basis by the corporation.  But as bond investors know, there's a
difference in yield-to-maturity depending on whether the bond is paid
annually, semi-annually or quarterly.  And it's all because of the
time value of money.

Google search strategy:
Investopedia "repurchase agreements" 

Best regards,

Omnivorous-GA