IMO manufacturers market oil filter names just like other things. I note that poor Sears is on verge of collapse. Strolling through their outdoor equipment section reveals "Craftsman" oil filters for $12 to $15 when the auto filter sits at $4-$5. The owner's manual warns that such "genoowine" filters are necessary to protect against heat of air cooled engines. IMO it is hype. My (now) reliable Intek uses auto filters. Sears has killed itself with markups that worked in the WWII era, but have not convinced the public that repainted chinese jackstands, for instanct, are worth twice the price.
So you found a catalogue that listed the mesh size, flow rate & bypass valve pressure rate for the filter on your mower and also the ones for the car filter you are using and checked they were both the same or close enough to the same ?
oil filters are like every thing else that gets made it is all about volume, volume , volume. Thus the most popular car filter will always be a lot cheaper than the most obscure mower filter.
As a general rule most car oil pumps shift about 10 times the flow rate of mowers at much higher pressures than a mower pump car oi runs at a fairly consistant 80 deg C whereas air cooled oil can oft get up to the 150 deg C mark.
A lot of car makers put the bypass valve in the oil filter housing so their oil filters do not have a valve in them which makes them a lot cheaper no vertical shaft lawn mower engines do this.
If I was selling oil filters for 351 chevies I could easily for off several thousand a month so I can make a reasonable living on a much smaller mark up.
If I was tryig to make a living selling intek oil filters I would be lucky to sell 1000 a year so naturally the mark ups will be higher as I will have stock sitting on my shelves for the better part of a year.
Next companies like Sears who you seem to delight in their downfall spend a lot of that exorbant mark up on things like service & keeping parts lists & service information available.
So next time you go to your cheapest possible car parts shop, ask them what pto belt fits your lawn mower, how to fit it and when can they get you one .