[請益] 為什麼UCO一直再轉倉?

Investments in WTI crude oil futures contracts are subject to position
accountability levels and position limits set by the listing exchange for suchcontracts – the New York Mercantile Exchange or “NYMEX.” On May 1, 2020
the Funds received notice from the exchange directing the Funds to not
exceed an exchange-designated position accountability level in the September
2020 WTI crude oil futures contracts.
In response to this notice, and to help manage the impact of significant
volatility and other market conditions, each Oil Fund intends to transition
1/3 of its portfolio exposure from the September 2020 WTI crude oil futures
contract into exposure to the December 2020 WTI crude oil futures contract bythe close of business on Monday, May 4, 2020. At such time, each Fund expectsto have approximately 2/3 of its portfolio exposed to the September
2020 WTI crude oil futures contract and approximately 1/3 of its portfolio
exposed to the December 2020 crude oil futures contract.

https://www.proshares.com/media/documents/PSTII_8K_05042020.pdf?param=1588695577832
大意是現在UCO有1/3是12月的倉，2/3在9月的倉
不過裡面提到基金收到NYMEX的通知不要"EXCEED"超過9月
既然不要超過9月為什麼又要轉1/3到12月呢?
有高手可以解釋一下嗎?謝謝

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