In a nutshell, ATF realizes that there are actually two reporting requirements when a theft/loss occurs that involves NFA items. An NPRM has been floated after much deliberation to streamline this process. Comments are due by November 10, 2014. http://www.gpo.gov/fdsys/pkg/FR-2014...2014-18874.htm

Here is the important paragraph:

Pursuant to 27 CFR 479.141 and according to the instructions on Form 3310.11, licensees reporting the theft or loss of a registered NFA firearm must provide additional notification to ATF. As discussed previously in section I, no form exists for this purpose, and the person reporting typically submits a letter with the required information to the NFA Branch. As part of this rulemaking, ATF is proposing to revise Form 3310.11 to capture the information required by 27 CFR 479.141. Therefore, a licensee would be able to satisfy the required notification to the NFA Branch by submitting Form 3310.11 to NTC, and NTC will notify the NFA Branch. Submitting Form 3310.11 will satisfy both requirements under 27 CFR 478.39a and 27 CFR 479.141 with one notification.