No specific number of approaches is required to be performed during the conduct of an instrument proficiency check. What is done is at the discretion of the instructor or check airman conducting the check, and attesting to the instrument proficiency of the person underoing the check.
You are required to have six approaches in six months to maintain currency...you are not required to have six approaches during the course of the IPC.
If you desire to get the six approaches, then good for you. You're making a smart decision. You can do more than six, too.
An IPC should generally include the same items that would be required on a checkride, though the person administering the IPC may elect to concentrate on specific areas such as maneuvering with an engine out for approaches and partial panel...which are things that most pilots don't do except during training.
The regulation, 14 CFR 61.57(d), only requires that a "representative number" of tasts from the practical test standards be administered, and the number of these tasks, and their type and appication, are at the discretion of the individual administering the check.
If you only performed one instrument approach during that check, it had better have been with one engine inoperative...and the examiner was pushing his luck.
This checkride may be used in place of a flight review, but will not cover your requirements for instrument proficiency unless you complete a representative number of tasks from the instrument rating PTS. If you've done this, you've met the requirement. No requirment exists for a logbook entry, though practically, you may have difficulty showing compliance without obtaining an entry stating that you passed.
In this case, your test was for instrument privileges in an airplane, specifically a multi engine airplane. You have been tested by an examiner for instrument privileges, and this will meet the requirement. The evidence is that you passed the check is that you have been issued a temporary airman certificate.
Personally, in such a situation, I ask the examiner for a signoff anyway. I amy not need it, and generally speaking over the years I've never needed an IPC or flight review because of the regulations under which I've operated and taken my checkrides. I ask for the signoffs anyway. The check airman, examiner, inspector, etc, always grumbles, and signs as requested.
In lieu of an IPC signoff in your logbook, you have your Form 8710 which will cite what was done for the ride and your status in meeting those standards (satisfactory), as well as the signature of the examiner attesting to the fact that you have met the standard. Always keep a copy. If anyone questions your accomplishment, this proof is indisputable.
Having said that, I'd strongly encourage you to go get further instruction and regular instrument practice and training in multi engine airplanes (and single, for that matter). While you may have met the technical requirements, (which should be irrelevant, because you ought to have done at least 6 approaches, holding, and tracking during your preparation for that practical test), but if the examiner only had you fly one approach, he was pushing his limits with respect to testing you on the bare minimum. Hopefully he also covered engin-out work on instruments, and other areas that pertain to your proficiency.
You can never get enough proficiency training, regardless of the regulation. Remember, the regulation sets a minimum standard. No law or regulation prohibits you from doing more, and doing it better. Good luck!
