Curently Cubobit does support Dash InstantSend 

This technology allows Dash to compete with existing centralized payment platforms. Dash InstantSend technology offers this, but in a decentralized way

These transactions work like the majority of the cryptocurrencies with a payment being issued instantly, but their security cannot be trusted until multiple blockchain confirmations, while the InstantSend option uses the masternode network to block transaction supplies for an additional fee, resulting in a transaction that is instantly secure and private. 

Keep in mind that currently, there are not many Dash Masternodes that are in use for this features at this moment. therefore Cubobit can not assure that the recipient of the transaction will receive the funds instantly. 

Standard transaction fee for Dash withdrawal: 0.002 DASH per KB transaction data. 

Dash instantSend fee per transaction: 0.001 

                                                                   Cubobit OU