On January $1,2019,$ Piper Company entered into an agreement with Save$-$Mart to sell its most popular product, the gadget. The contract stipulates that the price per unit will decrease as Save$-$Mart purchases higher volumes of the gadget, as follows:

Sales Volume

Price per Unit

$0$ to $1,000$ units $$50$

$1,001$ to $2,000$ units $45$

$2,001$ to $3,000$ units $40$

$3,001$ units and above $35$

The contract states that Save$-$Mart pays Piper the unit price based on the current sales volume. Once a volume threshold is reached, the price is retroactively reduced to the applicable price per unit. Based on its past experience with similar contracts, Piper believes that the total sales volume for the year will be $1,800$ units and uses the most likely amount approach to estimate variable consideration. In addition, Piper concludes it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur once the uncertainty surrounding the variable consideration is resolved.

Required:

$1.$ Determine the transaction price per unit that Piper should use to record revenue.

$2.$ Assume that Save$-$Mart purchases $800$ units in the first quarter of $2019$ and $900$ units in the second quarter of $2019.$ Prepare Piper$$s journal entries to record the sales in the first and second quarters.

$3.$ Given the higher than expected sales volume in the first half of the year, Piper increases its estimate of the sales volume to $2,800$ units. Prepare the journal entry to record this change in estimate.