I think this is a balanced post and I come to similar numbers...

I think this is a balanced post and I come to similar numbers myself. 

IPL sales price
We can look at this two ways:
1. East Coast market price less pipeline tolls = $8 to $10 market price less $3 to $4 pipeline tolls = ex field price of $4 to $6.
2. Disclosures in the financial statements.  Jun-18 financial statements note 15 (b)  provide the following detail:

"In June 2018 Macquarie Bank Limited novated its rights and obligations under the First Contract Year of the MBL Gas Sale andPrepayment Agreement (refer Note 18), to Incitec Pivot Limited through a new Gas Sale Agreement. There was no cash settlementoption under the novation. This resulted in an amount of $7,865,982 being transferred from Other Financial Liabilities to DeferredRevenue. Revenue will be recognised as gas is delivered to IPL."

MBL Gas Sale and Prepayment was for 5.2 PJ over 3 years or 1.73 PJ per year.  Given the detail above that the first contract year will be delivered to IPL in gas, it implies that the discounted (to Jun-18) ex-field gas price is $7.9m / 1.73 PJ = $4.54 a GJ ex-field.  Actual price will be scaled up by the rate they have discounted this at - my calculations show they use c. 5% when I recalculate the movement in prepaid gas liability but the goodwill calculation shows they use an internal rate of 14%.  Either way, and depending on the complexity of their workings, I calculate an ex-field price range of $4.77 to $5.18 (unwinding at 5% or 14% respectively).  

In summary, both 1. and 2. above point towards $5 GJ as a relatively accurate midpoint.

Going forward, prices appear to be softening but we should be able to achieve something similar (maybe higher) for CY 2020.  Spot LNG prices have been falling of late (c. $7 USD BTU) but it's pleasing (for us CTP holders) to see that the East Coast market still remains robust with prices around the $9-$11 mark for 2019/2020 marketing of gas:

Source: Cooper Energy CEO: Softer LNG market 'only shaves top off' domestic gas prices

IPL are also still hunting for gas post Dec-19:

"Another critical test for the east coast market is looming this year as Incitec Pivot hunts for gas for its Gibson Island plant near Brisbane to head off potential closure once its current supply contract ends in December.Incitec chief executive Jeanne Johns said earlier this month the company is "continuing to pursue affordable gas supply" to the plant to bridge between the end of 2019 and the anticipated start of production in 2022 from gas licences jointly held with Central Petroleum."

Source: East coast gas crisis sends Remapak to the wall

Marginal gas production costs
The only reference I have for the marginal opex costs for NGP production is from the Jun-15 quarterly(!).  Obviously this was 4 years ago, so we may need to esclate for some inflation to c. $1.20 GJ, but still relevant for a feel:

4th paragraph, MD report: "As a gas field, Mereenie is a low-cost conventional gas producer with marginal production costs fornew gas sales of around $1/GJ."

Source: June 2015 Quarterly Activities Report

Free cashflow
CTP have given guidance that in CY19, they expect to reduce net debt by c. $22m - this is your free cash flow figure.  This is including our costs for:
- Tie in and testing of PV13
- Ooraminna 3 commitment well
- Progressing further targets

We also have other free carried exploration of:
- Dukas 
- ATP 2031 

Source: 2018 AGM CEO presentation

EBITDA, net profit and cashflow
As Ash notes, there's a fair bit of accounting magic going on in the financials with various prepaid gas agreements - Take or pay ($13m), MBL ($23m) and now IPL ($5m).  In total these are c. $40m at Dec-18 and need to be repaid over c. 3 years (c. $15m in this CY2019).  After 3 years, we will have this all going to cashflow.

In summary, the 12 month run rate for CTP for the next few years going forward should show.....EBITDA will be high ($50 - $60m at guess), net profit will be positive ($20m-25m at a guess) and cashflow will be positive ($20-$25m per above).  All of these will be major achievements for CTP with 2 of the 3 never achieved before (from operations!).

Upsides to current production cashflow
- From a pure production point of view, we have additional capacity for spot sales especially if PV13 production testing performs.  At c. $4 GJ gross margin, this all goes to cashflow, so you can see how leveraged we are - 10 TJ/d would provide c. $7m cashflow if we achieved 6 months of spot sales.  
- CY20 sales contract.  Our 2019 sales contract to IPL looks like they we have provided them slightly better than market rates, probably for us to prove reliability?  Or maybe because they assisted us with some financing?  CY20 should enhance value by providing us with a steadier footing and any $ increase at delivery, will virtually translate straight to ex-field.  It's not unreasonable to think we could get $6 to $6.50 ex-field in CY20, providing upto an additional $10m per year of cash. 

For me, it's the most stable year that CTP has ever had but also the most exciting.