Tesco Pricing Obfuscation

I happened to be at Tesco's tea shelves this afternoon, checking the prices of my current favourite tea, Twinings Everyday. Is it a deliberate ploy, on the part of major supermarkets, to stealthily attempt to confuse customers with their pricing?

• Twinings' largest pack of tea, 240 bags, costs £4.99
• Tesco state that this equates to £2 per 100g
• Tesco states that Twinings 160 bag pack is about 78p per 100g. Yet, the larger pack is clearly the better value of the two. I cannot recall how much the 160 bag pack actually cost (let me know if you do). I enlisted the help of a fellow-customer beside me by asking him if he was any good at maths! He was compos mentis and agreed that the largest packet was best.
  

My fellow-blogger, Alan In Belfast, has pointed out this tea discrepancy before. Now I know exactly what Alan means!