Woocommerce Plugin for Custom Quantity Pricing

Hello, I need a Woocommerce plugin that enables me to list my products by the dozen or by each. A check box would be ideal. I need to be able to choose a price for each or dozen. Example is 1 dz is $5 per dozen, 6 dz is $3.73 per each dozen (6 * $3.75 = $22.50 ) , 12 dz is $2.50 (12 * $2.50 = $30 ). I need to be able to choose how many each or dozen (1 to whatever) and price per each or dozen. I also need to assign a shipping price for who many are ordered. So the same concept, but with shipping.. Example is: 6dz = 3.50 per dozen shipping (6 * 3.50) 12 dz = $2.50 per dozen shipping (12 * 2.50 =) This also needs to be added to sizes also. Small, Medium and Large and each has a set of 3-4 prices depending on how many they order. I order: 1 each Indian headdress, per each - $24.99 each 6 dz Tomtoms @ $12 per dozen - $72.00 1 dz Large Arrowheads @ $12.00 a dozen 6 dz Large Arrowheads @ $6.00 per dozen - $36.00 I want to be able to choose the quantity either each or (EA) or Dozen (DZ) in each product I want to be able to specify shipping rates behind the scene for each item so at checkout it calculates the correct shipping per item. So if someone orders 12 dozen the the shipping of that product calculated at the end is $25.80. For 48 dz the shipping is $23.40. I want to be able to set my shipping rate per item, not per total of the order and have it say step down 5 times per each item. I hope this makes sense. If there are any questions, please do not hesitate to contact me.