Why are the calculation formulas for the bolt seat bottom plate of tower-type containers different from those for the ear-type support bottom plate?

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Today I wondered why the calculation formulas for the bottom plate of the bolt seat in tower-type containers and those for the bottom plate of the ear-type supports are different. From the perspective of the bottom plate structure, it is supported by two rib plates; the outer side is considered free, while the area where the rib plates are located functions as a simply supported edge. The side that is welded to the cylinder is regarded as a fixed edge. Considering the bottom plate enclosed by these two rib plates, it has an approximately rectangular shape, and the appropriate formulas for two-dimensional rectangular plates can be found in structural statics calculation manuals to simplify the calculations ； The calculation formulas for the base plate in NB/T47003.1-2009 and NB/T47041-2014 are completely different from each other. Moreover, the coefficients in Table 15 of NB/T47041-2014 also differ significantly from those used in the manual for static structural calculations. It is unclear what calculation models were used to derive the calculation formulas for the base plate in NB/T47003.1-2009 and NB/T47041-2014