It seems like the question ultimately comes down to what is and isn’t an unnecessary delay, and when does that become a denial of a conference. We’re explicitly not allowed to deny a conference per the G2A. I read the section below regarding unnecessary delay of advancement in a larger unit to suggest that delaying any SMC until all other rank requirements have been completed could be understood to be an unnecessary delay of rank advancement, and potentially become a denial of a conference necessary to meet the requirements.
Personally, I hate “lawyering at” the regs & requirements, because it seldom leads to good feelings all around. At the same time, I try to understand how someone else might read the same words and understand them differently. I try to resolve things in a way that maximizes the benefit to the scout. Maximized benefit, however, isn’t always the same thing as fastest rank advancement, IMHO.
From the Guide to Advancement:
184.108.40.206 Unit Leader (Scoutmaster) Conference
The unit leader (Scoutmaster) conference, regardless of the rank or program, is conducted according to the guidelines in the Troop Leader Guidebook (volume 1). Note that a Scout must participate or take part in one; it is not a “test.” Requirements do not say the Scout must “pass” a conference. While it makes sense to hold one after other requirements for a rank are met, it is not required that it be the last step before the board of review. This is an important consideration for Scouts on a tight schedule to meet requirements before age 18. Last-minute work can sometimes make it impossible to fit the conference in before that time. Scheduling it earlier can avoid unnecessary extension requests.
The conference is not a retest of the requirements upon which a Scout has been signed off. It is a forum for discussing topics such as ambitions, life purpose, and goals for future achievement, for counseling, and also for obtaining feedback on the unit’s program. In some cases, work left to be completed—and perhaps why it has not been completed—may be discussed just as easily as that which is finished. Ultimately, conference timing is up to the unit. Some leaders hold more than one along the way, and the Scout must be allowed to count any of them toward the requirement.
Scoutmaster conferences are meant to be face-to-face, personal experiences. They relate not only to the Scouting method of advancement, but also to that of adult association. Scoutmaster conferences should be held with a level of privacy acceptable under the BSA’s rules regarding Youth Protection. Parents or guardians and other Scouts within hearing range of the conversation may influence the Scout’s participation. For this reason, the conferences should not be held in an online setting.
While it is intended that the conference be conducted between the unit leader and the Scout, it may sometimes be necessary for the unit leader to designate an assistant unit leader to conduct the conference. For example, if the Scoutmaster is unavailable for an extended period of time or in larger troops where a Scout’s advancement would be delayed unnecessarily, then it would be appropriate for an assistant Scoutmaster (21 years old or older) to be designated to conduct the conference.
Unit leaders do not have the authority to deny a Scout a conference that is necessary to meet the requirements for the rank. Unit leaders must not require the Eagle Scout Service Project Workbook, the Eagle Scout Rank Application, statement of ambitions and life purpose, or list of positions, honors, and awards as a prerequisite to holding a unit leader conference for the Eagle Scout rank. If a unit leader conference is denied, a Scout who believes all the other requirements have been completed may still request a board of review. See “Boards of Review Must Be Granted When Requirements Are Met,” 220.127.116.11. If an Eagle Scout candidate is denied a conference, it may become grounds for a board of review under disputed circumstances. See “Initiating Eagle Scout Board of Review Under Disputed Circumstances,” 18.104.22.168.