Hi, I have 2 sentences:
1."What time shall I be there on Monday?"
2."What time should I be there on Monday?"
Can we use "shall" and "should" interchangeably when asking for advice? Sentence N2 sounds better to me in this context and sentence N1 is more like the speaker himself doesn't know what time he or she will be there on Monday. But it's only my opinon, which may be wrong, hence this question.
No, 'shall' and 'should' are not interchangeable in questions.
"Shall I bite the head off this mouse? Shall I climb under this stationary train?" Depending on the calibre of your friends, the answer may be 'yes' or 'no'. It's asking whether they would like to see you do it.
Whether you should do these things is a different proposition.
For me, either is suitable in the original question.