JP side has thread saying the it takes too much time to obtain company seals from company leve's or turning in items and doesn't balance out with amount required to rank up. Rep responded to this one with following:

Quote Originally Posted by Mocchi View Post
こんにちは。
Hello,

パッチ1.20で高レベル向けのキャラバン護衛の追加などを行いましたが、パッチ1.21以降も「キャラバン護衛」や「カンパニーリーヴ」とは異なる新しいコンテンツの追加も含めて入手手段を増やしていきます。
We added new caravan security missions for high level players, and in patch 1.21 we will add new content which is different from caravan security or company leve to be able to obtain more company seals.

なお、軍票の取得量についてはパッチ1.20で調整を行っていることもあり、今後、取得量を大幅に増やすということは今のところ予定していません。
In 1.20 we have adjusted the amount of company seals you can obtain, therefore we are not planning to increase the amount at the moment.