SQL Fixlets need clarification on relevance version

I was looking at relevance for MS19-JUL: Security update for SQL Server 2016 SP1 CU15 GDR - SQL Server 2016 SP1 - KB4505221 (x64)

As per Microsoft KB page https://support.microsoft.com/en-us/help/4505221/description-of-the-security-update-for-sql-server-2016-sp1-cu15

Version: 13.0.4604.0

Relevance as per bigfix is

(exists keys whose (exists value "Version" whose ((it = "13" AND it >= "13.1.4001") of (it as string as version)) of key "Setup" of it AND exists value "PatchLevel" whose ((it >= "13.1.4001" AND it < "13.1.4604") of (it as string as version)) of key "Setup" of it) of (keys "HKLM\SOFTWARE\Microsoft\Microsoft SQL Server" of it) of (x64 registry) AND exists ((((if exists match (regex "\((.*)\)") of it then parenthesized part 1 of first match (regex "\((.*)\)") of it else it) of (if it contains "$" then following text of first "$" of it else it)) of display name of it) of services whose (exists file (first match (case insensitive regex "[^%22]*sqlservr.exe") of (image path of it)) whose ((it >= "13.1.4001" AND it < "13.1.4604") of product version of it)) , names of values of keys "HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL" of (x64 registry)) whose (item 0 of it = item 1 of it)) OR exists keys whose ((exists value "Version" whose ( (it = "13" AND it >= "13.1.4001") of (it as string as version) ) of it and exists value "PatchLevel" whose ( (it < "13.1.4604") of (it as string as version) ) of it) of key "CurrentVersion" of it) of key "HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\130" of (x64 registry)

My question is why are we comparing 13.1.4604 in fixlet relevance as Microsoft KB page has different version number.