XMLTV base time not equal to schedule time

Hello guys,

I have some problems with time conversion(?) that appears at some other sources, too. Maybe one of you can explain where the timeshift comes from or what I have done wrong in my configuration:

part of nelonen.fi.ini

(...)
site {url=nelonen.fi|timezone=Europe/Helsinki|maxdays=28|cultureinfo=fi-FI|charset=UTF-8|titlematchfactor=90|episodesystem=xmltv_ns|ratingsystem=MEKU|keepindexpage}
url_index{url|http://www.nelonen.fi/tvopas_json/|urldate|}
url_index.headers {accept=text/html,application/xhtml+xml,application/xml|contenttype=application/json}
url_index.headers {customheader=Accept-Encoding=gzip,deflate}
(...)

part of WebGrab++.config.xml

(...)
  <channel update="i" site="nelonen.fi" site_id="c4" xmltv_id="Nelonen">Nelonen</channel>
(...)

Part of JSON-File scraped as defined above from http://www.nelonen.fi/tvopas_json/|urldate| :

(...)
{
      "name": "Keno",
      "description": "Illan Keno-arvonnan tulokset. Arvonta on suoritettu Poliisihallituksen hyväksymällä arvontajärjestelmällä. Keno arvonnan tulokset myös Veikkauksen sivuilta www.veikkaus.fi. Kotimainen visailuohjelma. (2')",
      "starttime_timestamp": "1502128680",
      "endtime_timestamp": "1502128800",
      "hour": "20.58",
      "channel": "Nelonen"
    }
(...)

Test conversion of timestamp results in time as defined in „hour“ (20:58) so this is correct.

Part of guide.xml generated by WebGrab++ V2.1:

  <programme start="20170807175800 +0300" stop="20170807180000 +0300" channel="Nelonen">
    <title lang="fi">Keno</title>
    <desc lang="fi">Illan Keno-arvonnan tulokset. Arvonta on suoritettu Poliisihallituksen hyväksymällä arvontajärjestelmällä. Keno arvonnan tulokset myös Veikkauksen sivuilta www.veikkaus.fi. Kotimainen visailuohjelma. (2')</desc>
  </programme>

By definition, xmltv times are in UTC (source time plus UTC offset).
Following that we should have something like 20170807205800 -0300 in the XML.

What have I done wrong that this is not correct?

Thanks a lot for your help.

Best,
Tom