Help, insurance comparison

Hi I'm shopping for private insurances in Thailand. I have a few options with all similar prices. 

1. Cigna 

- Inpatient/ Cancer full coverage

- Cover area: Thailand and country of origin 

- Prescribed medicines that I take home after hospitalisation is not covered however.

- Max coverage usd500k, but max 250k per condition. (I'm thinking, who would have two major conditions in a year... I know it could happen, but it sounds like max coverage is only 250k per year to me) 

- Semi private room only (I read online that Thailand's high end hospitals such as Bumrungrad only have private rooms, in this case it cannot be covered right?)

- $1500 deductible per year

2. April TH 

- CInpatient / Cancer full coverage / 0 deductible

- Cover area: Worldwide Excl USA

- 16.375 Baht 60 days before and after the hospitalisation (it sounds like any medicines and drugs can be covered with a limit for non inpatient cases, which is slightly better than above plan)

- Private room

- I like this plan the most, however under the Terms and Conditions it states that "we can end your contract or increase premium due to high claims" whilst Cigna specifically mentioned that that won't. I mentioned this part to my AA broker and he said it's due to law they have to mention it, however it won't happen.... (true?)

3. April International 

- Inpatient / Cancer / 0 deductible

- Thailand only

- Two bed 

- Similar to others but in the benefits, it says "any treatment that's exceeding $2,000 needs prior approval from April" Is it normal? Same AA broker answered me "If you need to be hospitalized the Insurance Company always need to give a PRIOR APPROVAL if you want direct billing between company and hospital. All insurers work the same way. The hospital has to ask for it." Is it true? 

I'm very new to this insurance world... so I need to learn many details of TnC... please help me to choose the right one. 

Thanks,