Can you check in additional bags during a transit in DOH as long as you stay below your entire allowance?

For example, flying OSL-DOH-AKL in J, so 40kg (basic) allowance. If I check in a 25kg bag in OSL, through checked to AKL, can I add a 10kg bag in DOH (after shopping in the souk, for example) giving a total 35kg on arrival in AKL?

I am thinking that I will leave the airport during my transit with a spare bag, do some souvenir shopping, then go to the baggage counters at DOH before passing security and continuing on with my flight. I might buy things that are either a bit heavy to carry on board, or not allowed in hand baggage.