for me both paragraph same meaning because both the paragraph contain 1.5 test pressure??
(c) if the test pressure as defined above would produce
a nominal pressure stress or longitudinal stress in
excess of the yield strength at test temperature or a
pressure more than 1.5 times the component rating at
test temperature,
the test pressure may be reduced to
the maximum pressure that will not exceed the lesser
of the yield strength or 1.5 times the component ratings
at test temperature.