It struck me recently that, for many people, it's not the second but the third heart scan that more commonly shows a reduction in score.
I think this is because many people's reaction to their first heart scan is "This can't be. There's no way my arteries have that much plaque." They then follow a half-hearted program to correct their patterns.
When the second heart scan shows a significantly higher score, that really catches their attention. This is when they finally buckle down and give it their all.
Only the occasional person will, after the first heart scan, seize full control and take their program very seriously. These tend to be highly motivated people.
Don't feel too bad if your second heart scan score shows an increase. Look at it for what it represents: feedback on the adequacy of your program.