Tasco was a brand and bought in whatever to fit their target market.
At some point some Jap tooling went to Taiwan and continued to produce the same scope. I have identical Jap/Taiwan 3-9x40 Prohorns. The change was circa 1992?? Later, Tasco bought from other factories including Korea. To me the quality was lost when Deben took the agency, circa 1995??

A whole lot of budget scopes were bought from China from 1995 onwards, because they were astonishingly cheap. Loads of new brands all selling inexpensive scopes from China, all before China knew how to make a half decent scope. Most were truly rubbish. It took a while for China to be educated how. Much thanks goes to the bigger brands doing their own designing, and investing in new foreign machines for China. Design and new machinery, plus better educated quality control, means there are good Chinese scopes to be had now. However, innovation doesn't come from China, nor the best glass and coatings. Lasers in manufacturing is the reason cheap and precision is possible; thats real progress. Especially true to lens manufacture.