Mercedes G500, 2004, Engine RPM

Hello friends,
My next patient is a Mercedes G500, manufactured in 2004.
I am running the drive scan (CAN-C) at 500 kbps.

I'm looking for the ID and bytes related to the motor speed, and I thought I found them: ID 0x308, bytes 1 and 2. The resulting value increases with increasing speed, but it shows very large jumps from 3200 decimal to 250 decimal at idle, even without applying a multiplier.

Here are the frames I logged:

-> 0x328 8 BF FE 77 00 00 FF 00 00 ..w..... 24998 ms
-> 0x200 8 0A 48 00 00 00 00 00 00 .H...... 24998 ms
-> 0x208 8 00 20 60 00 00 00 00 00 ..`..... 24998 ms
-> 0x300 8 80 88 80 00 80 00 80 1B ........ 24999 ms
-> 0x248 8 00 04 00 00 00 00 00 00 ........ 25018 ms
-> 0x230 1 08 . 25007 ms
-> 0x238 4 00 1E 88 14 .... 26118 ms
-> 0x236 8 0F EC 10 00 40 FF FF 8A ....@... 26129 ms
-> 0x312 8 06 C1 0C 44 0C 44 0A 99 ...D.D.. 30222 ms
-> 0x308 8 00 00 00 02 00 78 88 3C .....x.<30222> 0x338 8 00 00 1F FF FF FF FF FF ........ 25004 ms
-> 0x218 8 80 00 DD 48 23 80 35 25 ...H#.5% 25005 ms
-> 0x418 8 50 FF 88 80 DD 00 C0 00 P....... 25005 ms
-> 0x428 1 02 . 25720 ms
-> 0x210 8 02 00 00 00 40 80 7E 00 ....@.~. 30212 ms
-> 0x212 8 03 23 4A 99 6A 99 8A 99 .#J.j... 30213 ms
-> 0x410 8 80 1C 00 00 00 70 00 00 .....p.. 25030 ms
-> 0x240 8 00 12 00 00 10 00 FF 00 ........ 25013 ms
-> 0x408 8 2A A8 8E 00 00 00 E2 10 *....... 25064 ms
-> 0x412 8 00 00 00 00 00 01 00 00 ........ 25065 ms
-> 0x40E 8 64 00 00 00 00 00 00 00 d....... 24948 ms
-> 0x608 8 7E 56 2A 0E D2 00 00 FF ~V*..... 30132 ms
-> 0x580 8 64 64 64 FF 96 00 00 00 ddd..... 30133 ms
-> 0x6FA 8 03 33 36 34 FF FF FF FF .364.... 24143 ms
-> 0x631 8 FE 00 A1 10 0E 06 03 00 ........ 24652 ms
-> 0x101 8 41 48 00 00 00 00 00 00 AH...... 20730 ms
-> 0x111 8 03 63 9F 1E 00 00 00 00 .c...... 20203 ms

Does anyone have a suggestion, please?
Best regards, Frank.