Dell Latitude Silent BIOS Update Issues

I manage a fleet of Latitude series laptops, and am trying to update the BIOS's of my machines en-mass.  I've downloaded the latest BIOS files from Dell's website, and all the documentation I've read indicates that I should be able to silently install them to my machines.  I'm using a very simple .bat script to accomplish this--all it does is check the computer model, and silently installs the corresponding BIOS executable. 

@echo off

for /f "tokens=2 delims==" %%f in ('wmic csproduct get identifyingnumber /value ^| find "="') do set "serviceTag=%%f"

for /f "tokens=2 delims==" %%a in ('wmic computersystem get model /value') do for /f "delims=" %%b in ("%%~a") do for %%m in ("Latitude E6330") 

do if /i "%%~b"=="%%~m" (set "model=%%~m" goto start)

echo un-compatible system
goto :eof

:start
echo Start of script for model [%model%]

IF "%model%"=="Latitude E6330" (
    start .\E6330A20.exe /s /forceit /l="C:\Logs\BIOS Logs\BIOS_Log_%serviceTag%.txt"
	)

Exit

The problem I'm running into is this: The logs indicate the Dell BIOS Update utility is running successfully on all my computers, but the BIOS does not flash upon rebooting on most machines.  In my testing, approx. 75% of my machines are not installing the BIOS update upon a reboot.  In the example logs below, I can see that the utility ran and the machine was pending a reboot.  At the end of the day, the computer was shut down.  When powered back on, the bios did not flash. 

***BIOS flash started on 10/3/2018 at 9:37:24***
Command: C:\DistributedFiles\E7440A25.exe /s /forceit /l="C:\Logs\BIOS_Log_XXXXXXX.txt"

A22 INSTALLED (Dell System Latitude E7440)
- Intel Management Engine (VPro) Update : 9.5.62.3002
- System BIOS : A22
- Embedded Controller : A14
- Legacy Video OROM : 2178.V.15
- Legacy RAID OROM : 12.7.0.1936


A25 UPDATE (Dell System Latitude E7440)
- System BIOS : A25
- Embedded Controller : A14
- Gigabit Ethernet : 0.6
- Legacy Video OROM : 1039.V.17
- Legacy RAID OROM : 12.7.0.1936
- Intel Management Engine (VPro) Update : 9.5.62.3002
- Intel Management Engine (Non-VPro) Update : 9.5.60.1952
- ACPI OS support : 0.0.0.1
- Intel AntiTheft : 3.0.0.18

Exit Code = 2 (Reboot Required)
***BIOS flash finished at 10/3/2018 at 9:37:35***

Are there any known limitations with these BIOS update utilities that I'm missing?  I really don't want to put a force reboot switch into my script--it would be a huge inconvenience to my users if their machines started randomly rebooting during the day.  If anyone else has gotten this to work, I'd appreciate advice. 

Thanks!