Question about Coolife 3-teiliges Hartschalenkoffer-Set mit TSA-Schloss

Hello Why is this bundle https://www.galaxus.ch/de/s8/product/coolife-3-teiliges-hartschalenkoffer-set-mit-tsa-schloss-93-l-koffer-57830962 the big suitcase (93l) is bigger than this bundle with backpack? https://www.galaxus.ch/de/s8/product/coolife-3-teiliges-reisegepaeck-set-93-l-koffer-54095227 The only difference is that this product has a bag and not a backpack. Why are the dimensions different, even though both are 93 litres? My airline only allows the total length to be 158 (length, depth and width together). The set with bag is 161cm according to the specifications. Is it possible that this is wrong?