Are you familiar with the term 'aerocap/aeroshell'? If not, put it in the Search box in the upper left.
Your present cap suffers because of the square cross-section of the cross bars and interference drag between the cross bars and the top. The high rise cap goes in the wrong direction, increasing the size of the hole the vehicle punches in the air.
It's hard to say which would be worse, but they won't be better.
Comprehensive list of aerodynamic pickup caps/aeroshells on EcoModder (& elsewhere)
See a trend here?