Tesco cooked chicken says 300 kcal for 240g — how is that possible?

I bought a pack of Tesco cooked chicken breast (240g total), and the label says:

• Per 1/6 pack: 199kJ / 47kcal So the whole pack is around 282–300 kcal.

That seems really low. From what I understand, 240g of cooked chicken would come from around 300–320g of raw chicken, which should be closer to 360-380, depending on how lean it is.

Curious if anyone else has noticed this or can explain it.