OM - The info you have scanned appears to be late 1940's information, and was obviously current at that time. The chart I scanned is from the early 955 OMI, dated 1955, and is no doubt, a revised offering from Cat on starting temperature guidelines.

There were regular design improvements to starter motors, batteries, and engines, in the intervening period, and this obviously led to Cat revising the starting temperature guidelines after a number of years.

There are propane, LP powered block heaters out there if you are far from a cord.