It seems that using the A3 app, that when booking a multi-city RT, I seem need to do two separate bookings. Let me elaborate...

I want to fly LIS-ATH-FCO on April 2nd, 2023 (because of prices) and return on April 9th, 2023. Using the A3 app, when using the multi-city function/tab I can only book 2 flights at a time. Thus I can only book flying to FCO on one booking, THEN I must make another separate booking to fly back to LIS.

Is this the way it is, or am I doing something wrong? Would I get a lower total price if I were to put all on one PNR? I am booking all sectors in Economy Comfort Flex because it seems that Economy option (from past experience) gives me the best chance of using my vouchers to upgrade to Business Class.

Thoughts? Suggestions? Thank you.