Why do the Saitek and DGT brand clocks only show the seconds remaining at times of less than 20 miutes?

On both brands, the clock "jumps" from an hour:minute dispaly to a minute.second  at 19.59. A colon is used between hour and minutes and a period is used between the minutes and seconds . So that 20m looks like this 20:00 but 19m 59s looks like 19.59. Why not show a minute/second display at all times less than an hour?   Why not have the clock jump at 59m59s, so that an hour remaining is 01:00 but the on the next second the clock would jump to 59.59?

Is this an European thing? Both companies are HQ'ed in Europe. DGT in the Netherlands and Saitek in Germany (I think?) Is this a FIDE or ECU recomedation? 

Of the 3 game clock companies HQ'ed in the U.S.A, DCI (makers of Chronos & SamTimer), Sensionite(maker of Duel Timer), and Excalibur*(maker of Game Time II), thier chess clocks all show the exact # of seconds remaining at all times.  So I assume the jump clock at the rather arbitrary  20 minute mark must be an European thing.  Right?  

Why less than 20 minutes? Why not 25? or 30? or 45? or an HOUR? 

BTW I think if the Saitek Pro did show seconds at all times less than and hour and it had quieter operation buttons, it   considering its low price and full line up of features, would be the perfect chess clock. 

*Excalibur was recently bought by another company and may no longer be Head Quatered in the States, but it was when the clock model was designed.