以下内容出自一本美国出版的战争历史书籍（《When Titans Clashed》出版社为University Press of Kansas。这本书籍最早于1995年出版，2015年再版，并有扩充与修改）

Malinovsky struck again on 5 December, this time north and south of Budapest in a two-pronged attack to seize the city. Kravchenko’s 6th Guards Tank Army and Pliev’s cavalry-mechanized group advanced to envelop the city from the north via Sahy; a second force, spearheaded by Lieutenant General K. V. Sviridov’s 2nd Guards Mechanized Corps, advanced south of Budapest from small bridgeheads over the Danube River, which the Soviets had seized in late November. From there, this second force secured Székesfehérvár and Esztergom, west of Budapest.

 *通过下文得知，这次进攻行动中，文中的 “this second force”远未达到其目的地（Székesfehérvár and Esztergom），也就是说这里的一般过去时的叙述指的是过去将来的计划而非已经发生的事实，这种一般过去时表示过去将来的计划的用法是否妥当？

 我是去年读完的这本书的，我读的版本是2015年的新版，当时我发现这个问题时，觉得可能是句子有错误，于是找到了1995年的旧版，最后一句话于新版有差异。旧版对应的一段如下：

 Malinovsky struck again on 5 December, this time north and south of Budapest in a two-pronged attack to envelop and seize the city. Kravchenko's 6th Guards Tank Army and Pliev's Cavalry-Mechanized Group advanced to envelop the city from the north via Sahy, and a second force, spearheaded by Lieutenant General K . V. Sviridov' s 2d Guards Mechanized Corps, advanced south of Budapest from small bridgeheads over the Danube River seized in late November to secure Szekesferhervar and Esztergom, west of Budapest.

 旧版中to secure不定式作目的状语，表示过去将来的计划应该是合理的，但是新版中，主句用一般过去时的secured表示过去将来的计划，却又不在任何从句中，这是可接受的吗？有没有可能是新版在修改语句时出现的错误？是否应该改成“From there, this second force was to secure Székesfehérvár and Esztergom, west of Budapest.”

希望得到专家老师们的意见，谢谢！