Unable to access all needed Credentials for Refresh in OAuth flow in Custom Connector

I have found a solution for my approach and have also seen another option that may be viable. The solution I am using is to set the RefreshToken in credentials as the value "access_token;refresh_token;access_code" as these are the three variables that I need. I do this by taking the TokenResult from Web.Contents and renaming or setting the Record Fields corresponding to access_token and RefreshToken:

JsonResponse = Json.Document(TokenResult),
JsonRenamed = Record.RenameFields(JsonResponse, {{"token","access_token"}, {"refreshToken", "RefreshToken"}}) & 
            [RefreshToken = JsonResponse[token] & ";" & JsonResponse[refreshToken] & ";" & code, Expires = 900]
    in
        JsonRenamed;

I can then call Refresh as 

Refresh = (dataSourcePath, tokens) => 
    let
        TokenList = Text.Split(tokens, ";"),
        accessToken = TokenList{0},
        refreshToken = TokenList{1},
        code = TokenList{2},
   ...
   in  
       output

The second option I have seen uses oldCredential to store and access all the old information. This is most likely cleaner, but I have not verified if it works with adding a custom field to the Credentials record to store the special access_code I need. You can see more examples of this technique here: https://community.fabric.microsoft.com/t5/Developer/Custom-Connector-failing-on-refreshing-data-with-multiple-calls/m-p/2608325