For which models was 2^3>8?

[Joe Horn]

According to my best attempt to pinpoint the moment when 2^3 began to equal 8 in the evolution of HP calculators, I've compiled the following partial table of model introductions in historical order:

HP-35  1972-07
HP-80  1973-02
HP-56  1973-04
HP-66  1973-04
HP-45  1973-05
HP-65  1974-01
HP-70  1974-08
HP-55  1975-01
HP-21  1975-02 ???
HP-25  1975-08     2^3>8
========================
HP-22  1975-09     2^3=8
HP-91  1976-03
HP-27  1976-05
HP-25C 1976-07 ???
HP-67  1976-07
HP-97  1976-07
HP-10  1977-07
HP-29C 1977-07
HP-92  1977-07
HP-19C 1977-09
HP-97S 1977-12

Therefore the accuracy improvement seems to have happened between the inaccurate HP-25 (introduced August 1975) and the accurate HP-22 (introduced one month later). HOWEVER that leaves me with two questions:

(1) This implies that the HP-21 used the old inaccurate math, but I don't have one to verify that on. Could somebody with a real physical HP-21 (no simulators please) please check whether it returns 8.000000002 or exactly 8? Be sure to set DSP 9 of course.

(2) This also implies that the HP-25C is more accurate than the HP-25, which I highly doubt. Could somebody with a real physical HP-25C (not 25, and no simulators please) please check whether it returns 8.000000002 or exactly 8? Be sure to set FIX 9 of course.

Thanks in advance!