Loop only adding one result - for-loop

Question

Situation:
For each customer, make a purchase, subtract inventory from seller, add money to sellers account.
// for each customer
for ($c = 1; $c <= $maxCustomers; $c++) {
// decide what to buy
$willBuy = rand('1','7');
// buy indica
if ($willBuy == '1') {
// how many eights are they going to buy..
$willSpend = rand('1', '4');
if ($indicaPrice < $averageIndicaPrice) {
if ($indicaAvailable > $willSpend) {
// update products
$newIndica = $indicaAvailable - $willSpend;
update_user_meta($sellerID, 'Indica', $newIndica);
// pay for purchase
$newCash = $cash + $indicaPrice;
update_user_meta($sellerID, 'cashOnHand', $newCash);
echo "<tr>";
echo "<td>#".$c."</td>";
if ($willSpend > "1") { echo "<td>".$willSpend." 8th's of Indica Flowers</td>"; }
else { echo "<td>".$willSpend." 8th of Indica Flowers</td>"; }
echo "<td>$".$indicaPrice * $willSpend."</td>";
echo "</tr>";
}
else {
echo "<tr>";
echo "<td>#".$c."</td>";
echo "<td>Could not find anything they liked. No sale.</td>";
echo "<td>$0</td>";
echo "</tr>";
}
}
}
}
Problem #1: In the 'update products' section, it's only updating for 1 loop result. If there is more than one customer who buys 'indica' it only update the indica meta value for 1 result, not for each result (ie, if 2 people buy 3 indica each, it will only subtract 3 indica not 6).
Problem #2: The same thing happens in the 'pay for purchase' section. It only updates the cash for one purchase, not for each purchase.

Answer 1

You are never changing $indicaAvailable are you? Shouldn't you update it based on what was sold?