Manual TDC entry when in automatic mode?

[Wisq]

Having played SH3, SH4, and Dangerous Waters on and off for a while, I decided to combine the immersion and campaign of SH4 with the sneakiness and sensing ability of Dangerous Waters. I installed the 688i SSN mod on top of SH4, did a test campaign mission (periscope depth / radar depth attacks with auto targeting), and all was well -- if obviously horribly unbalanced.

So then it was time to restore some of the difficulty by employing proper SSN procedure, i.e. deep operation and EMCON. I started using MoBo to do pure passive sonar-based TMA on a lone merchant ship, got an excellent solution. So I figured I'd start punching data into the TDC ...

Trouble is, none of the knobs will turn. They work fine in manual mode, but it seems that auto TDC completely disables the ability to enter data manually -- and unlike SH3, there's no manual override button. (Except oddly, there is a manual override if you're driving a U-boat.)

Am I missing something, or is there literally no way to do manual solutions when you've got auto TDC? I'm all for trying 100% manual for a bit (with or without the periscope), but I was sorta hoping to be able to mix it up on a whim, rather than defining it at mission start and that's it.