Using wix to install a windows service that may already be installed - wix

Question

I'm using WiX 3.1.1 to install an exe and a service. Sometimes, the MSI install fails with a fairly generic error:
Error 1923. Service 'MyService' (MyService) could not be installed.
Verify that you have sufficient privileges to install system services.
Experimentally, this appears to be because the service already exists, and my xml uses Vital="yes"
I would like to have the MSI ensure the service is installed, but accept (or repair) it if it's already present. It sounds like I should set Vital="no", will this cause it to ignore other errors? Is there a way to limit what kind of errors are ignored? Is there a best practice I'm missing?
For reference, a redacted snippet of my xml:
<Component Id="REDACTED" Guid="{REDACTED}" Win64="yes">
<File
Id="filB754EE270009E240193A8279D1529A43"
Name="myservice.exe"
KeyPath="yes"
DiskId="1"
Source="SourceDir\File\filB754EE270009E240193A8279D1529A43" />
<ServiceControl
Id="MyService"
Name="MyService"
Start="install"
Stop="both"
Remove="uninstall"
Wait="no" />
<ServiceInstall
Id="MyService"
Name="MyService"
Type="ownProcess"
Start="auto"
ErrorControl="normal"
Vital="yes"
Account="[SERVICEACCOUNT]"
Arguments="svc -config "C:\Program Files\MyService\conf\service.flags""
Description="My Service">
<ServiceConfig
ServiceName="MyService"
FirstFailureActionType="restart"
SecondFailureActionType="restart"
ThirdFailureActionType="restart"
ResetPeriodInDays="1"
RestartServiceDelayInSeconds="5"
xmlns="http://schemas.microsoft.com/wix/UtilExtension" />
</ServiceInstall>
</Component>