LTE + Gives less speed in my case may because of low network as LTE+ signals comes and goes frequently (depends on location comes at certain locations only), and here Jio deployed CA on 40+40 Bands (20mhz+10mhz) that could be a issue here, Usually get 4~5 MBps speed at normal LTE and 1~2 MBps at LTE+, i am from Nashik, Maharashtra and Using device
Mi A1, Check SS for more clarification.