No Mixdown Option to Synchronize Audio - Only Option is Track 1

[#1]

Premiere Pro 14.4

Source: Video/Audio FS7 4-Channel mono tracks.

Sync Track: 788T-Mono Wave

-Both at 48k 24bit

Only Channel 3 from FS7 has audio (Third Audio Track has audio)

Empty tracks deleted or left it doesn't matter.

Clap Sync Points recorded and can be matched mannually. 

Problem or Misunderstaning?

The Sync Audio option only offers to Sync to Track 1, no mixdown option or other track options avaible.

[#2]

Premiere Pro 14.4

Source: Video/Audio FS7 4-Channel mono tracks.

Sync Track: 788T-Mono Wave

-Both at 48k 24bit

Only Channel 3 from FS7 has audio (Third Audio Track has audio)

Empty tracks deleted or left it doesn't matter.

Clap Sync Points recorded and can be matched mannually. 

Problem or Misunderstaning?

The Sync Audio option only offers to Sync to Track 1, no mixdown option or other track options avaible.