Thats because most the games were draws back then. If he had not made those big scores in the draws, they would have been losses for Pakistan.
2nd Test: Pakistan v India at Lahore, Oct 27-Nov 1, 1978 | Cricket Scorecard | Cricinfo.com
3rd Test: Australia v Pakistan at Melbourne, Dec 11-15, 1981 | Cricket Scorecard | Cricinfo.com
2nd Test: England v Pakistan at Lord’s, Aug 12-16, 1982 | Cricket Scorecard | Cricinfo.com
1st Test: Pakistan v Australia at Karachi, Sep 22-27, 1982 | Cricket Scorecard | Cricinfo.com
2nd Test: Pakistan v Australia at Faisalabad, Sep 30-Oct 5, 1982 | Cricket Scorecard | Cricinfo.com
2nd Test: Pakistan v India at Karachi, Dec 23-27, 1982 | Cricket Scorecard | Cricinfo.com
3rd Test: Pakistan v India at Faisalabad, Jan 3-8, 1983 | Cricket Scorecard | Cricinfo.com
ODIs
2nd ODI: England v Pakistan at Birmingham, Sep 3, 1974 | Cricket Scorecard | Cricinfo.com
12th Match: Pakistan v Sri Lanka at Nottingham, Jun 14, 1975 | Cricket Scorecard | Cricinfo.com
6th Match: Australia v Pakistan at Sydney, Dec 17, 1981 | Cricket Scorecard | Cricinfo.com
9th Match: Australia v Pakistan at Melbourne, Jan 9, 1982 | Cricket Scorecard | Cricinfo.com
2nd ODI: Pakistan v Australia at Lahore, Oct 8, 1982 | Cricket Scorecard | Cricinfo.com
2nd ODI: Pakistan v India at Multan, Dec 17, 1982 | Cricket Scorecard | Cricinfo.com
4th ODI: Pakistan v India at Karachi, Jan 21, 1983 | Cricket Scorecard | Cricinfo.com
22nd Match: New Zealand v Pakistan at Nottingham, Jun 20, 1983 | Cricket Scorecard | Cricinfo.com
1st ODI: Pakistan v England at Lahore, Mar 9, 1984 | Cricket Scorecard | Cricinfo.com
1st ODI: Pakistan v India at Quetta, Oct 12, 1984 | Cricket Scorecard | Cricinfo.com
4th ODI: Pakistan v New Zealand at Multan, Dec 7, 1984 | Cricket Scorecard | Cricinfo.com
2nd ODI: Pakistan v Sri Lanka at Gujranwala, Oct 23, 1985 | Cricket Scorecard | Cricinfo.com
& this one was a loss but still cant leave it out.
2nd SF: Pakistan v West Indies at The Oval, Jun 20, 1979 | Cricket Scorecard | Cricinfo.com
Im not going to try to answer the Miandad comment, too many games to cite.