Dear KAur Ji
I havent read the Lecture by Bhai SAhib Randhir Singh JI , But would like th epoint out that the translation you have choosen to read above is not litereal translation and so not fully correct
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=9122
the word dhhath /Dwqu does not mean Universe instead it means element
so in the above Line it means that although many religious book give no of worlds but even then all of it is composed of same element that is GOD / AKAL Purakh itself
Here is the alternate translation by Bhai Manmohan Singh ji :
ਸਹਸ ਅਠਾਰਹ ਕਹਨਿ ਕਤੇਬਾ ਅਸੁਲੂ ਇਕੁ ਧਾਤੁ ॥ सहस अठारह कहनि कतेबा असुलू इकु धातु ॥ Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=9122 sehas athaarah kahan kataybaa asuloo ik Dhaat. The Semitic scriptures say that there are eighteen thousand worlds, but in reality there is only one essence; that the Lord is limitless.
I Hope it helps .
Jatinder Singh
Thanks