כָּל־אֵ֜לֶּה אֲבָנִ֤ים יְקָרֹת֙ כְּמִדֹּ֣ת גָּזִ֔ית מְגֹרָר֥וֹת בַּמְּגֵרָ֖ה מִבַּ֣יִת וּמִח֑וּץ וּמִמַּסָּד֙ עַד־הַטְּפָח֔וֹת וּמִח֖וּץ עַד־הֶחָצֵ֥ר הַגְּדוֹלָֽה׃
All these were of costly stones, according to the measures of hewn stones, sawed with saws, within and without, even from the foundation unto the coping, and so on the outside unto the great court.
Rabbeinu Bahya
ואלה בני דישן, “these are the sons of Dishan, etc.” This is the same Dishan mentioned earlier in verse 21, the fifth son of Seir HaChori. Sometimes the Torah spells his name דישון; other times it spells the name דישן. It is the same person each time. We find such differences in the spelling of the names of one and the same person elsewhere, such as in Kings where Chirom is sometimes spelled חירם other times חירום (compare Kings I 7,9). This principle applies only when these names appear in different verses. When both spellings appear in the same verse, however, it is clear that two different people of similar names are meant. The spelling is changed so that we become aware that the Torah refers two separate people.