Ultra Races/Randonneuring

Year or so Training Plan user here. Is there any use in changing or getting a different plan for specifically Ultra cycling, compared to just using the advanced Gravel Plan, after 18 weeks of SS Advanced Plans? I’m just wondering if something with maybe a bit less intensity and more training time in the saddle would be useful but I’m not completely sure if that makes sense because of the FTP Push/Pull idea all the plans are based on. I’m planning on doing some 200Ks in the summer during my SS period (late start to training this year) instead of two seperate rides on the weekends. And hopefully have a 400 or 500 done by the end of the year. If you could give me some feedback, that be great. Thanks!