Additional Inventory without Sales

I suspect that it is just showing your actual deduction on the tax return, which is $0.

Merely purchasing Inventory does not result in a tax deduction.  The deduction happens when the product is sold (and therefore your inventory decreases).

I think, based on your description, tis would be the error: "In the "Tell us the Cost of Your Goods" window, TTx shows $10,000 for 2014 Cost of Purchases. I typed in $5,000 for 2015."

Purchase = what you spent to get new inventory as an Asset. Not as expense.

Cost, meaning your purchase price, of Goods Sold, and Sold means Gone. You stated that 2015 had no sales, so COGS is $0 for 2015.

$10,000 inventory purchased and still on hand for the end of 2014 + $5,000 new product on hand = total of $15,000 inventory asset on hand. Nothing sold = $0 COGS.

Cost of Purchases while on hand = inventory Asset value. It's not a cost of goods Sold, until they get Sold.

Then:

Gross Income from sales minus COGS = profit for what you sold. Example:

$15,000 on hand value

sell one third of it, for 100% markup

That means $10,000 value still on hand <== asset

and;

$10,000 gross sales income <== $5,000 cost of products sold at 100% markup

minus $5,000 Cost for the goods sold and no longer on hand

= you made $5,000 profit, which was the plan, since you used 100% markup

And this is Fine: "the Buss. Income & Expenses Summary" shows "0" no matter if I type in "0" or "$5,000" in this field."

Having new inventory or not, makes no difference to Expense, because you had no sales.