Per Besta instructions, it says to connect another unit by screwing them into holes 3 and 7. Any idea why these? Can I use other holes? Doesn't seem uniform like this. :
IKEA BESTA CERNIERE Di Chiusura Morbide X2 Versione Attuale Nuovissima Prodotto Ikea Originale EUR 6,95 - PicClick IT