It is indeed because of that. 37.5% coverage from curation implies that we are able to recover 37.5% of our voting value in curation rewards. Since only 25% of vote values goes into curation, that means we are 'outperfoming' by 50%.

1.34x voting rewards may still be too high. We temporarily decreased it on comments already (to 1.15x) to help VP recover. Sustainability Coverage just dipped below 100% today, although I will double-check all the data before making any changes to member rshares growth rates). This also means we will actively power up instead of leasing delegations until Sustainability Coverage rises above 100% again. If that results in another decrease in VP below 15%, we will further cut voting rewards to 1.25x on regular updates and 1.10x on comments until VP recovers.

It's all a fine balance and we have a lot of levers we can pull now, though the impending loss of conversion income means we are not in quite as strong a VP position as we would like to be when shifting to power-up instead of delegation.