It looks to me like the VMS has both a short c-shape and a long c-shape in various parts of the manuscript, and the one in your example on the left looks to me like a long c-shape with a tail (a connected macron).
It also seems to me that the VMS has both a short a-shape and a long a-shape and your example on the right looks to me like a long a-shape.
Some transcription systems acknowledge the long-c shape and even include it in their alphabet, but I haven't seen one that includes the long a-shape (maybe Glen Claston's system has long a-shape but I haven't seen his system yet and won't have time to look at it in the near future).
Even though I've done 4 transcripts, I am not at all sure if there is a distinction between long-a and short-a, but I am pretty sure there is a distinction between long-c and short-c.
It also seems to me that the VMS has both a short a-shape and a long a-shape and your example on the right looks to me like a long a-shape.
Some transcription systems acknowledge the long-c shape and even include it in their alphabet, but I haven't seen one that includes the long a-shape (maybe Glen Claston's system has long a-shape but I haven't seen his system yet and won't have time to look at it in the near future).
Even though I've done 4 transcripts, I am not at all sure if there is a distinction between long-a and short-a, but I am pretty sure there is a distinction between long-c and short-c.