You still need to eat 260g of cooked lentils to equate to 200g of cooked meat and then you will still not get the same amount of beneficial protein as the meat as a study by the CSIRO has already debunked.
What you forget is human physiology and that includes the absorption of the beneficial nutrients in food in a nut shell it is why we are omnivorous our body only has one stomach, which is our main processing plant, this is were the bulk of nutrients are extracted from, most herbivorous animals have a further 2 to 4 stomachs for this and is why unlike us they can extract the further proteins from greens and the process takes much longer it can take up to 4 days from beginning to end, ours has max 24hrs and even then this is a generalization as it should take less than this, ever wondered why when you wake up in the morning the first thing you need to do is take a s^%T it's our bodies resetting getting rid of the waste from the day before.
As for iron intake it still takes 2kg of green leafy veges a day to give the ordinary person person the RDI of iron as opposed to 200g of meat/fish or poultry.

"Your born, You Live, You Die, given this premise, one can conclude since we have no control over when we are born and when we die, the only thing that matters to us should be how we live, simple really?" Mis-Cat to her philosophy Lecturer.