NTM Version: 1.0.27X4431
The default NTM fallout config has different min and max ranges for several block conversions (fallout entries). Several fallout entries also have differing "primary conversion" chances. None of these parameters (minDist, maxDist, primaryChance) nor the "isSolid" tag are read from hbmFallout.json. Additionally, when writing the default config to _hbmFallout.json, minDist and maxDist are not written, nor is the "isSolid" tag.

The above paragraph in table form:
Parameter Missing Operations (R/W) Used in default config?
minDist RW Yes
maxDist RW Yes
primaryChance R Yes
isSolid RW No

Should be fixed in X4438, haven't tested it though.

Finally got around to testing hbmFallout.json after over a month (using version 1.0.27 X4474), here are the issues I've noticed:

1. Chances in the config that are below 100% are treated as 0% due to it being read as an integer instead of a double.
2. maximumDistancePercent is read as minDist, overwriting the value from minimumDistancePercent.

Should be fixed in X4476.