Man, that many bundled would need to be derated as well.
310.15(B)(3) Adjustment Factors.
(a)
More than Three Current-Carrying Conductors. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or
multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in
Table 310.15(B)(3)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
Not sure if your site qualifies under 511, but if it does you may have Class 1 requirements and it then prohibits the use of NM.
511.1 Scope.
These occupancies shall include locations used for service and repair operations in connection with self-propelled vehicles (including, but not limited to, passenger automobiles, buses, trucks, and tractors) in which volatile flammable liquids or flammable gases are used for fuel or power.
NM allowed in specific construction types
334.10(3)
Other structures permitted to be of Types III, IV, and
V construction. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.
Informational Note No. 1:
Types of building construction and occupancy classifications are defined in NFPA 220-
NFPA 220
4.6 Type V (111 or 000) Construction.
Type V (111 or 000) construction shall be that type in which structural elements, walls, arches, floors, and roofs are entirely or partially of wood or other approved material. [
5000:7.2.6]
Of course if there is no codes being followed and no enforcement, then it doesn't matter what the code says. Sounds like you are working in the Electrical Wild West, and everyone is carrying a gun and does as he pleases.