I know your FFR very well! You got one of the best!
Y'all don't need to overthink this LOE/LOA thing too much.
They are 2 very different creatures. LOA - WP commits to give you an appointment if you meet xyz conditions. LOE - WP (at that date) thinks you are a very good candidate (you've met certain thresholds) and wants to encourage you to keep WP on your radar screen. LOEs are to encourage the candidate without any commitment by WP to offer an appointment.
The appointments gong out this week are being given to those that have won a vacancy (either MOC or service-connected) or if they have a LOA + a nom (does not need to be a vacancy winner).
There are probably some without LOEs that are in that 374 number of appointments that went out this week. If you are 3'd and the clear cut vacancy winner, then you will get an appointment - LOE or not. Some LOEs are not going to hear anything now as they may not be the vacancy winner - either because the vacancy winner can't be determined yet (MOC hasn't turned in their slate or an incomplete application, or there is a DoDMERB issue or a CFA issue, etc) or they are not the top of the slate by WCS on a competitive slate or are not the P-nom on a ranked slate. Some LOAs may not hear now bc their MOCs have not submitted their slates yet.
All that to say - DO NOT BE DISCOURAGED if you have a LOE or LOA or neither and are not in this first wave. These are the appointments that are clear cut. It does not mean that you are any less competitive. Not all MOC slates are in. Not all applications are complete. Not all remedials/wavers have been resolved. Not all files have been qualified. It will all become clearer by 31 Jan - the MOC deadline to submit their slate(s). Clearer by 28 FEB - the application deadline.
Many more of you will hear. It's the wait game now. I look forward to seeing more names on the appointment list!