Variable TTF has different HHEA ascender/descender values than OTF

Prerequisites

[ ] If you are reporting an issue that affects glyphs for characters for a particular region or regions, did you verify that the characters are within the supported scope of the region or regions? This generally means GB 18030 or Tōngyòng Guīfàn Hànzìbiǎo (通用规范汉字表) for China, Big Five or CNS 11643 Planes 1 & 2 for Taiwan, HKSCS-2016 for Hong Kong, JIS X 0208, JIS X 0212, and JIS X 0213 for Japan, and KS X 1001 and KS X 1002 for Korea. Not applicable
[x] Did you thoroughly search the open and closed issues to avoid reporting a duplicate issue?
[x] Did you go through the official font readme file to better understand the scope of the project, to include the Known Issues section at the very end?

Description

From https://github.com/adobe-fonts/source-han-sans/releases/download/2.004R/SourceHanSans-VF.zip, the TTF versions of the font contains different HHEA ascender and descender values than that of OTF versions.

TTF has ascender, descender = 1000, -200:

$ ttx -o - -y 0 -t hhea Variable/OTC/SourceHanSans-VF.ttf.ttc
Dumping "Variable/OTC/SourceHanSans-VF.ttf.ttc" to "<stdout>"...
<?xml version="1.0" encoding="UTF-8"?>
<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="4.42">

Dumping 'hhea' table...
  <hhea>
    <tableVersion value="0x00010000"/>
    <ascent value="1000"/>
    <descent value="-200"/>
    <lineGap value="0"/>
    <advanceWidthMax value="3000"/>
    <minLeftSideBearing value="-991"/>
    <minRightSideBearing value="-519"/>
    <xMaxExtent value="2930"/>
    <caretSlopeRise value="1"/>
    <caretSlopeRun value="0"/>
    <caretOffset value="0"/>
    <reserved0 value="0"/>
    <reserved1 value="0"/>
    <reserved2 value="0"/>
    <reserved3 value="0"/>
    <metricDataFormat value="0"/>
    <numberOfHMetrics value="65532"/>
  </hhea>

</ttFont>

OTF has ascender, descender = 1160, -288:

$ ttx -o - -y 0 -t hhea Variable/OTC/SourceHanSans-VF.otf.ttc
Dumping "Variable/OTC/SourceHanSans-VF.otf.ttc" to "<stdout>"...
<?xml version="1.0" encoding="UTF-8"?>
<ttFont sfntVersion="OTTO" ttLibVersion="4.42">

Dumping 'hhea' table...
  <hhea>
    <tableVersion value="0x00010000"/>
    <ascent value="1160"/>
    <descent value="-288"/>
    <lineGap value="0"/>
    <advanceWidthMax value="3000"/>
    <minLeftSideBearing value="-991"/>
    <minRightSideBearing value="-519"/>
    <xMaxExtent value="2930"/>
    <caretSlopeRise value="1"/>
    <caretSlopeRun value="0"/>
    <caretOffset value="0"/>
    <reserved0 value="0"/>
    <reserved1 value="0"/>
    <reserved2 value="0"/>
    <reserved3 value="0"/>
    <metricDataFormat value="0"/>
    <numberOfHMetrics value="65532"/>
  </hhea>

</ttFont>

ttx is from fonttools 4.42.1.

adobe-fonts / source-han-sans

Variable TTF has different HHEA ascender/descender values than OTF #457

Prerequisites

Description