wyupdate /uninstall in wix

I use Wix for my installation. It's been recommended here to run wyupdate /uninstall (only on uninstall of course) when doing so, which I am doing as follows. This is from my Wix script:

<!-- Run wyUpdate /uninstall only on uninstall --> <CustomAction Id='run_wyupdate' FileKey='wyupdate' ExeCommand='/uninstall' Return='asyncWait' />

<InstallExecuteSequence> <Custom Action='run_wyupdate' After='InstallValidate'>REMOVE ~= "ALL"</Custom> </InstallExecuteSequence>

And here is the relevant part of the Wix log when uninstalling:

MSI (s) (10:98) [10:11:34:873]: Doing action: run_wyupdateAction ended 10:11:34: InstallValidate. Return value 1.MSI (s) (10:98) [10:11:34:876]: Doing action: InstallInitializeAction start 10:11:34: run_wyupdate.MSI (s) (10:98) [10:11:34:879]: Machine policy value 'AlwaysInstallElevated' is 0MSI (s) (10:98) [10:11:34:879]: User policy value 'AlwaysInstallElevated' is 0MSI (s) (10:98) [10:11:34:879]: BeginTransaction: Locking ServerMSI (s) (10:98) [10:11:34:879]: Server not locked: locking for product {57897008-A8E1-4BB3-A99C-88919D976EF3}Action start 10:11:34: InstallInitialize.MSI (s) (10:98) [10:11:37:676]: PROPERTY CHANGE: Deleting ProductToBeRegistered property. Its current value is '1'.MSI (s) (10:98) [10:11:37:678]: Note: 1: 2205 2: 3: Class MSI (s) (10:98) [10:11:37:678]: Note: 1: 2228 2: 3: Class 4: SELECT `CLSID` FROM `Class` WHERE `Icon_`=? AND `Class`.`Attributes`=1 MSI (s) (10:98) [10:11:37:678]: Note: 1: 2205 2: 3: Class MSI (s) (10:98) [10:11:37:678]: Note: 1: 2228 2: 3: Class 4: SELECT `Component`,`CLSID` FROM `Component`,`Class` WHERE `Component`=`Component_` AND `Icon_`=? AND (`Component`.`Installed` <> 0 AND `Component`.`Action` <> 0) MSI (s) (10:98) [10:11:37:678]: Note: 1: 2205 2: 3: Extension MSI (s) (10:98) [10:11:37:678]: Note: 1: 2228 2: 3: Extension 4: SELECT `Component`,`Extension` FROM `Component`,`Extension`,`ProgId` WHERE `Component`.`Component`=`Extension`.`Component_` AND `ProgId`.`ProgId`=`Extension`.`ProgId_` AND `ProgId`.`Icon_`=? AND (`Component`.`Installed` <> 0 AND `Component`.`Action` <> 0) MSI (s) (10:98) [10:11:37:678]: 'cboardico.exe' icon will be removed.Action ended 10:11:37: run_wyupdate. Return value 1603.

Two questions. First, is after InstallValidate the right time to execute this? Second, does the behavior from the log look correct? The uninstaller appears to do the right thing, but I have no idea what the 1603 return value means.

Thanks in advance,Aaron Haspel