LAST on HP20S

[jbhp55]

Dear rprosperi,

that's what I thought it should do, and it sometimes does. However, if I type:
1
+
1
=
(result: 2)
LAST

then the result is not 2, but an older result. (in my case 36).

If I then start a new calculation:
1
+
LAST, the output is again 36, and not 2 (the manual says that the last result is available as soon as a new operation is started).

This behaviour may be intended, but to me it is not clear which number is stored in LAST. This is particularly problematic in programming.

It seems that = stores something in LAST, but not for immediate use. LAST itself stores its outcome in LAST, overwriting the last result after =. Functions like sin, cos, tan do not store their result in LAST.

I cannot discover the logic behind this behaviour.
Can you?

Best regards,

Jaap.