Confused about the router IPs, help appreciated

[leveller]

I have the DGND3700v1. IPs below not the actual ones.

It has the IP 192.168.0.1 assigned to it and it uses DHCP to auto assign IPs to the LAN.

It has an external IP assigned by the ISP 86.126.24.57 and when I visit a site which shows my IP this is the one shown to the outside world.

The confusing part is my Gateway IP Address, which I assumed was something to do with NAT. This has IP 187.38.123.98. This IP is neither revealed by visiting sites nor revealed on the LAN. However, if I do a TRACERT the results are as follows:

freetrace to www.bbc.co.uk, 64 hops max, 52 byte packets

*hop(1) 92 bytes *192.168.0.1
*hop(2) 36 bytes *lns15.inx.dsl.enta.net (187.38.123.98) my gateway IP address
*hop(3) 36 bytes *gi1-5.inx.dist.dsl.enta.net (187.38.123.97) my gateway IP address minus 1
*hop(4) 36 bytes *te2-2.interxion.dsl.enta.net (78.33.141.89)
*hop(5) 36 bytes *te2-3.interxion.core.enta.net (86.126.236.209)
*hop(6) 36 bytes *te4-2.telehouse-east.core.enta.net (86.126.236.137)
*hop(7) 36 bytes *bbc-gw0-linx.prt0.thdoe.bbc.co.uk (195.66.224.103)
*hop(8) ******************** *Request timeout
*hop(9) ******************** *Request timeout
*hop(10) 36 bytes *ae0.er01.telhc.bbc.co.uk (132.185.254.109)
*hop(11) 36 bytes *132.185.255.148
*hop(12) 64 bytes *212.58.244.68

*----- END TRACE ------

Surely if my Gateway IP Address is my NAT address then it shouldn't show in a TRACERT, and why am I hopping to another IP with the same IP minus 1 in the last octet?!?!