I can see the fix that you are in. Corn oil is a staple for Chicago deep-dish doughs. It is used, along with a small amount of olive oil, by Malnati's and Gino's East if what is reported on this forum is correct and up to date. Home Run Inn uses all corn oil for its flat pizzas. In its early days, Giordano's used a mixture of vegetable oil and margarine, but the total fat content was only around 6%, and I don't know what form the vegetable oil took. Based on the feedback of the members of this forum, I cannot see using 21% olive oil, even if price were not an issue. It's also hard to imagine using 21% margarine or shortening, and I don't know what blend of oil and solid fat would be cost effective or functional on the palate. As for the form of the solid fat, that is, liquid or solid, if it is liquid it can be treated the same as oil. If it is solid, it can be added in that form to the flour in the mixer bowl without having to liquify it. If you are using magarine, depending on the amount that you would use as part of the final blend, you may have to adjust the formula hydration to reflect the fact that margarine is about 17% water.
We have some members who are experts on the Chicago deep-dish style and oil/fat levels for that style. Maybe they can offer up a possible solution, bearing in mind that you are in Japan.