The Tiger Ausf.B's glacis is 150mm thick and sloped at 50 degrees from vertical, the Jumbo's glacis is 100mm thick and sloped at 47 degrees from vertical ! So as you can see the Tiger Ausf.B is enormously better protected from the front than the Jumbo, you can't even compare the two !
And since the Jumbo had a pea-shooter of a gun it was a Cow on the battlefield, no match for the KingTiger which could knock it out at distances exceeding 2km. Heck even the Tiger Ausf.E could take out the Jumbo frontally at a distance of 1km, just by aiming at the turret. The Panther could do the same at a 1.5km distance. Truth is, against the AT and tank-guns of the time, the Jumbo was anything BUT impervious to AT fire.
Here are 2 Jumbos hit by 88's
The first Jumbo had 1 hit bounce of the glacis and 2 off the mantlet before a 4th entered through the gunsight opening in the mantlet.
The last 2 pics are the same Jumbo that was disabled by a mine. It then took 8 hits from 88's. 7 failed to penetrate and only one (no.3) got in and set it alight.