The inversion distance between the chloroplast DNAs of Marchantia polymorpha (mp) and Nicotiana tabacum (nt) is 7.  To illustrate the sequence of gene order changes,  the genomes are represented in a condensed form as following:
  gene 19-->1 is renamed as gene 1
  gene -20-->-54 is renamed as gene 2
  gene 55 is renamed gene 3
  gene -56-->-72 is renamed gene 4
  gene -73-->-74 is renamed gene 5
  gene 75-->-81 is renamed gene 6
  gene 82 is renamed gene 7
  gene 83-->-86 is renamed gene 8.
So the dataset becomes:
mp
3 -5 -1 2 4 6 8 -7
nt
1 2 -3 4 5 6 7 8

These two genomes can be divided into two parts, i.e., gene 1-5 corresponding to LSC, gene 6-8 corresponding to IR-SSC. They two parts can be viewed as independent to each other.

:

1. To translate (6 8 -7) into (6 7 8), there are two ways, each requiring two inversions

flip 8 in mp, then flip (-8 -7), i.e.
   (6  8 -7)
-->(6 -8 -7)
-->(6  7  8)

alternatively, flip (8 -7) in mp, then flip -8.
   (6  8 -7)
-->(6  7 -8)
-->(6  7  8)

2. There are many choices to translate (3 -5 -1 2 4) into (1 2 -3 4 5), 
The total number of possible ways is around 1000. One of the possible scenarios is:
    (3 -5 -1  2  4)
--> (3 -5  1  2  4)
--> (3 -5 -2 -1  4)
--> (3 -5 -4  1  2)
--> (3 -2 -1  4  5)
--> (1  2  3  4  5)

The total sequences are any combination of the above two parts:  2 steps + 5 steps = 7 total inversion steps to transform the gene orders between the Marchantia and Nicotiana chloroplast genomes.