Visas are valid from the date of issue usually for 90 days (unless it's a long term Visa) so don't apply too soon as it will be valid for entry usually for just 90 days from the date of issue
You cannot be issued a normal Visa or Extension beyond the expiry date of a passport. I think your friend got a new passport as the old one was nearly full so in this case he would get the full Visa or Extension and had the stamps transferred to the new passport. [DTV, LTR and other non-normal Visas can be issued beyond the expiry of a current passport]
The fact you didn't take the 30 day extension will possibly work in your favour as you did not max out your first stay then try to re-enter soon after to repeat. Have the 3 proofs just in case you are questioned :
- proof of accommodation for at least your first few nights (hotel booking or a letter of invite from a Thai)
- proof of onward travel (international travel ticket leaving Thailand within your initial entry stamp exit by date)
- proof of funds (20,000 Baht or equivalent in any major currency in CASH per individual, or 40,000 for a family)