Marcelle and Amia each buy two “Treat Dispenser” shirts from Ava’s website for $22 each. They live in South Dakota, where the sales tax is 6.4%. Marcelle calculates his total bill by finding the sales tax for each individual shirt, multiplying by 2, and then adding it to the retail price of both shirts. Amia calculates her bill by adding up the total cost of both shirts, finding the sales tax of the sum, and then adding it to the retail price of both shirts. Whose method is correct, and what was the total bill for each of their orders?