Bitrate output file just 33% of CBR bitrate in settings (4K ultra HD in premiere elements 15)

Hi

Am using premiere elements for quiet a long time. With version 15 I have problems with exporting a project.

I use 4k AVCHD and with the standard 4k ultra HD settings the qualitie should be 100Mpbs (standard settings). If I render the file it is just 34mpbs. Also if I change it manually to 100Mbps CBR the output doenst change. Please help? (Please dont ask why I use 100Mpbs or why I want CBR instant of VBR, the problem is if I use the settings I want premiere to export in that settings not 1/3 of the target settings)

best regards,

Arjan