Did you use your Cirrus (5 string I presumed?) as your main prior owning the BTB846SC?
I thought those who have been familiar with the low B string wouldn't have such hard time adjusting to 6 or even 7 string bass, cause when playing these basses we view the strings from the top where we see the same the low B on top. At least it didn't happen to me when bought my first 6 string bass after played 5 string only for 22+ years, nor a couple of years later when I got the BTB 7 string.
The new thing to me was learning to mute more strings of which I couldn't use my fretting hand thumb to mute the low B by grasping the neck as I some times could on my 5.