Misleading Chord-Name placement

[Trevor Skeggs]

When chord names are placed below a system, they can be much nearer to high
notes in the system below (or even touch them) than to the bass notes of the
system above (to which it is supposed to refer). 

Obviously, system separation varies with the number of ledger lines intruding
into the gap between systems. With a pair of systems separated by 14mm, the
chord-name baseline is 10mm below the stave to which it refers and 4mm above the
stave below.

With a pair of systems in which a low C (second ledger line below the bass
stave) happens to directly align with a high E (third ledger line above the
treble stave), separation is 17.5mm, and chord-name is 13mm below stave (8mm
below the low C and touching the high E). 

Please, can anyone tell me the magic incantations required to draw the
chord-names closer to the bass notes and to put some extra space from the system
below?

Maybe I am creating a situation in not having the chord-names above the top
stave, but harmonic structure is easier to read with the chord-names near the
bass note.

This situation currently prevailing in 2.13.13 and previous

Thank you